Michael

Personally I’d be willing to pay well in excess of $20K for a V8Z that very closely meets my personal tastes and interests, but the price level drops quickly even if the workmanship is spectacular but the character of the car isn’t what I prefer. A couple of beers and I’d gladly pay $40K for a brutal, completely stripped tube-chassis car weighing <2200 lbs, that runs in the 9’s – on 87 octane, without nitrous or turbo/blower/supercharger, with a conventional manual transmission – and (very important for me) that can achieve that time even if shifted at 4000 rpm. Because I’m a hamfisted dweeb who likes to launch at idle and can’t tell apart a dragster from a yard tractor. But if the car meets the above specs, I don’t care if it’s a Z, a Camaro or a Yugo (as long as it’s converted to RWD). And I really wouldn’t care about the paint job, whether the various lights or gauges work, or if there’s rust in the rocker panels. If you have a car like that for sale, the cashier’s check is in the mail. Why? Because by the time I invest in tools, experience and parts to get such a car built, it would have cost well over $40K, at a significantly lower level of performance. And this isn’t the sort of car that Troy Trepanier or So-Cal Speed Shop would build for you, even if you showed up with a suitcase full of $100 bills. On the other hand, I wouldn’t even pay $10K for a nice “well rounded†car with a crate 350, 700R4, pro paint job and cream-puff interior, that runs 13’s but requires 6500 rpm shifts to get there. But some people would snap-up the latter example for double the price, and would value the former example no higher than scrap metal. So, yes, it all depends on finding the right customer.

For over a year I’ve been shopping for a “small†mechanical roller cam from my 454. Lift in the 0.600â€-0.640†range and duration around 235-240 degrees. A company called Cam Motion has semi-custom grinds in that range, but none of the big-name manufacturers have a mechanical roller cam that small; the choices are custom grind, or having to go hydraulic.

Not to hijack this thread, but I have essentially the same problem on a ’92 BMW 325is that I just bought; it has a later-generation Bosch engine management system. Does not stumble/miss when cold. Happens when the car is warm, below 3000 rpm, also at idle. No problem above 3000 rpm. Occasional backfire through exhaust, accompanied by sulfur-like smell. Idle when warm is unstable (hunts between 600 and 1100 rpm). These cars have an individual ignition coil per cylinder (no distributor). Neither timing nor mixture are adjustable.

It amuses me when automobiles are compared to masterpiece paintings, sculptures, etc. The purists say that modifying car XYZ is like “Add[ing] some color to that Picasso [painting]â€. Hmm… I wonder if Picasso painted the exact same painting 500,000 times on an assembly line, inside a factory, using machines to hold the brush and mix the paint. I prefer to think of modifying a car as modifying a $10 poster-print of the Picasso on sale at Wal-Mart. Sure, the poster is a rendition of a great work of art, but it’s just a mass-produced facsimile. Adding color to the poster does nothing to defame Picasso’s original. If the incandescent lamp lighting my room makes the poster’s colors look pale, I’ll go ahead and alter them – because it’s my poster, and my $10.

Do the OEM LSI blocks really go for around $500? That's quite amazing, to me at least. Aftermarket aluminum blocks go for $3500 and up! (that's Gen I SBC; Mark IV BBC, with which I am somewhat more familiar, are even higher - typically much higher).

Well, to return to the beginning of this thread... Yeah, for some reason most V8 conversions for sale have 3-speed automatic transmissions, and fall into one of two categories: lots of customization with questionable overall effect, or a “just dropped in the engine, hooked it up and got it running†conversion. The former would take lots of effort/money/time to undo the 9†fender flares, sunroof and built-in jacuzzi/wet bar; the latter needs new frame rails and rocker panels. Back when I lived in Los Angeles I’d find a V8 Z for sale in the “Recycler†newspaper at a frequency of one maybe every couple of months. A particularly memorable one was a “Nordskog†(sp?) special, complete with elaborate documentation of its history. Its claim to fame was that it had an emissions system that passed California smog check in the 1980’s, when such swaps were rather rare, especially street-legal ones. Definitely something of historical interest. Well, the thing was in such poor mechanical condition that it had a hard time reaching 25 mph on the residential streets where I test drove it. Which reminds me of the recent “how much will it cost to do a swap†thread on the Chevy forum. I considered buying some one else’s project as a route towards cost savings. But after realizing how much would have to be changed to get the car to fit my personal interests, and how much restoration would be required on all but the priciest swaps, it made more sense to start from scratch. Nevertheless... is Jim Biondo’s Z still for sale? Now that one was a genuine deal!

The guys who do manage the swap for $2000 (that figure strikes me as unbelievably low, but let’s accept it for the sake of the discussion) are veteran mechanics who have owned Datsuns for many years, know what to spot in a used car that’s for sale, know how to distinguish a solid engine from a blown engine 99% of the time, already have all of the tools that they need for the swap, and will fabricate nearly every part needed for the conversion. They’re also lucky; skill and patience alone are NOT sufficient to get the absolute best deals. A more realistic figure for cost, if you already have a “rust-free†car, do nothing to modify the suspension and only replace those components necessary to install and safely fit with the engine – is on the order of $2K PLUS the engine and transmission. A typical car with moderate rust, rotted bushings in the suspension, questionable brakes, inadequate wheels and tires… and an amateur mechanic who still needs to buy tools such as MIG welder, drill press, torque wrench,… figure about $6K, not counting the car. If you make mistakes, such as screw up an engine build and cause internal engine damage – add several thousand dollars for each such mistake. In fact, it’s the big mistakes and the midcourse revisions that really drive up the cost. There are cars on this site that are all-around competent vehicles – attractive, well-built hot rods which run in the high-12’s – and cost the owners $30K+ to build. That’s with the owner doing most of the work. And there are guys who have spent $10K, maybe $20K – whose car STILL doesn’t run, and won’t run for years – never mind paint jobs or functioning air conditioning or any of those frills. Bottom line: if you need to ask “How much?â€, you probably can’t afford it.

We need to distinguish between (A) “it can be done†and ( “it’s worth doingâ€. A – yes. B – probably not. The 240-280Z has relatively high drag and large positive lift because, perhaps contrary to intuition, it has “sharp edges†(hood lip, headlight scoops, others places) where it shouldn’t and smooth inclined surfaces (rear hatch, rocker panels) where it shouldn’t. So, it’s 0 for 2. Pleasing to the eye does not mean pleasing to the wind! Simple experiments with a scale-model Z reveal extensive regions of flow separation – meaning, high drag. Consider that some hot rods based on Model-T and Model-A Fords are running in the low 200’s at Bonneville. So it can be done. But keep in mind how much modification was required to get there. The record-holding 2+2 260 Z was built to adhere to very stringent class rules. This makes the guy’s achievement all the more impressive. But, relax those rules, and the same car could go much faster. So, again: it can be done. But is it worth it?

It is not necessary to “flatten†the springs after a coil is cut – the springs will still sit securely in their perches, because the stock spring perches have enough helix angle to accept the unflattened spring ends. At least, this has been my experience with a 280Z, with one coil cut from each spring.

I have a 1978Z with a 454 big block Chevy engine (pictures at link in Pete’s post). The car was built mainly for “street†purposes, but chassis reinforcement and various other mods were so extensive that street driving will be sparse, to say the least. BBC vs. SBC is one of the great debates in grassroots hot rodding. For the same peak hp numbers, the BBC will be more streetable and reliable than the SBC. It will run smoother and stock parts will survive more abuse. But aftermarket parts are much more expensive. For example, the cheapest aftermarket BBC heads begin at $1700 fully assembled, and most are > $2000. In terms of weight, the BBC block weighs about 230 lbs vs. the SBC’s 180 or so. The crank is about 15 lbs more. The big weight difference is in the heads – about 60 pounds. Figure another 30 pounds weight difference in odds and ends. With a cast-iron block but aluminum heads, intake, water pump, flywheel, etc., the BBC will still be around 80-100 lbs heavier than a comparably built SBC. With the advent of large displacement small blocks, 406†and above, I think that the balance has shifted in favor of the SBC for street-driving purposes. And I say that as a BBC owner. A BBC Z is something to build only after you already have a SBC Z under your belt. Keep in mind the two extremes of advice: most guys who haven’t done it are likely to consider it next to impossible. But, those guys who have done it are invariably veteran hot rodders, whose definition of “a little extra work†differs from the mainstream. I am not a veteran hot rodder, so I paid a friend to do the metalwork. In my car, the front clip was cut off, the firewall and floor were cut out, the floor pan was shorted, a mild-steel tube frame was built on a jig and welded into the car. Then the firewall/floor were welded back in, then the front clip, then the missing segments of frame rails and sheet metal were reconstructed. The transmission tunnel was reworked to fit a Doug Nash 5-speed, the steering linkage was reworked to accommodate the firewall setback, the seats mount to the roll cage, the dash is gone because it conflicts with the cage’s dash bar, the radiator mounting is completely redone, and so forth and so on. The engine is so far back that the distributor sits just 2†forward of the windshield – and the car is still 51/49 (nose-heavy), but that’s with cast iron heads. Because it was completely gutted, the car weights about 150 lbs less than stock. With a stock suspension (one spring coil cut at each corner, plus the JTR bumpsteer mod – otherwise completely stock suspension), the car sits higher than stock. No, you don’t need such extensive mods to swap in a big block, and if you already have a complete engine lying around, the extra costs of a big block are moot. I started from scratch, and in my view it only made sense to build a blood-and-guts race car if I were to go to the trouble of swapping in a big block. In terms of just getting the BBC to fit where a SBC already fits, it really isn’t that much extra work. The extra work is in making refinements to the car commensurate with the theme of a big block. Talk about the “while I’m at it†syndrome in the extreme. As for hood clearance – with a high-rise dual-plane intake manifold (such as Edelbrock Performer RPM) and the stock 9â€-deep oil sump, either the sump will hang well below the frame rails or the air cleaner will hit the hood. My hood had a hole in it, with the air cleaners sticking through. Later I covered the hole with sheet metal and fiberglass. Anyway, to summarize my views as a BBC Z owner: considering the costs, the extra fabrication, the aftermarket support for small blocks and the various challenges involved, I would recommend tackling the big block swap only if you have extensive hot rodding experience. E-mail me at ol_70@hotmail.com for more details.

Mike, Is this another "here we go again" again? I thought that you decided, once and for all, to hold on to that Z - especially after the engine came back together?!

This was asked before (I vaguely recall reading the post), but I couldn't find it - so, to ask again... How long can an assembled short block be stored on an engine stand, before the assembly lube leaks out from the bearing journals, necessitating tearing into the rebuild? After a month on the engine stand, I noticed some leakage from the crank main bearings. I was wondering how many more months I could safely wait, before full assembly and break-in.

I would make a strong distinction between profanity as a general expression of disaffection with the world, vs. a direct attack. If I read a post about how some one got [fill in your favorite profanity]’ed by a car dealership or the DMV, and wants to share his rant, I don’t find that offensive. The man has a right to voice his frustration in the company of friends. But if one member refers to another in a post as “incompetent†or “ignorantâ€, for example – that’s offensive, even though the words in question are by themselves entirely suitable in polite company. So the point is, avoid confrontational and accusatory language even if it avoids any “dirty wordsâ€, but don’t necessarily self-censor dirty words just because your third-grade English teacher would not have approved. The issue of profanity reminds me of letters to the Editor at Hot Rod magazine, whenever they print pin-up photographs of women. Invariably there will be letters from irate readers, lambasting the editors for their “immoralityâ€, corruption of youth, betrayal of the public trust, and general lack of decency. I look at these remarks through the eyes of a person who used to live in a totalitarian country. They remind me so much of “betrayal of the revolution†and “enemy of the peopleâ€. The natural border for freedom of expression is not transgression of the community's sensitivities, but intentional confrontation against individuals. For which profanity and expression of “vice†are neither necessary nor sufficient. I would argue that the main distinction between “now and “then†wasn’t the language per se, but the context. It used to be that the larger the common denominator, the more sanitized the language. Television, being perhaps the most common denominator of all, had tremendous and invasive limitations under the Hays code. But compare the novels of James Joyce or D.H. Lawrence – eminent writers of their day – to today’s literature. I doubt that you would find the latter “less†offensive. For the older fellows on this forum, please consider how machine shops around the country looked 50, or even 20 years ago; posters of you-know-what all over the place. Walk into a machine shop today, and it’s completely sanitized. So which is the more ribald? It used to be, and in some countries is still the case, that men would never swear in the company of women, but would heartily swear when amongst themselves. We have liberalized some “traditionsâ€, but tightened others. The common-denominator thinking at its core means that what’s not suitable for children should not be publicly aired. I disagree completely, because such thinking implies that it is our collective responsibility to raise each other’s children. The presumption is that kids will watch whatever is on TV, so nothing on TV should have obscenity, “if all were right in the world." I would argue that the real “threat†on internet forums is that irresponsible people will hide behind the anonymity of the internet, to hurl insults without fear of reprisal or censure. It’s like going to the zoo, to poke a ferocious wild animal in the eye, without fear because the animal can’t reach out of its cage. If we expressed ourselves on the internet with the same deference to one another that we use in face-to-face conversations, the issue of profanity would be moot.

Grumpy, Could you include a few words on how the break-in procedure differs for roller cams, especially mechanical rollers? By the way, for moderately aggressive lobes (say, 0.630" lift in a big block, 240 @ 0.050" duration) in engines that are serviced often but rarely street-driven (a few hundred miles per year, maybe 1000 miles/year max), what is the basis of the often-claimed advantage of hydraulic roller over mechanical roller?

500 hp is about the upper range for "stock" unibody cars on HybridZ, where "stock" includes a roll cage, strut tower braces, subframe connectors, etc. Most cars, even among the dragstrip heroes, are at 400 hp or less. There is a handful of tube-frame cars approaching the 800 hp range. They are the purpose-built race cards to which some of the above posts alluded. Examples includes Ron Jones, Japtin, and Ratsun (try a search on those names). Point is, no one here has cracked the 1000 hp barrier - apart from bench racing, of course. If you have the engineering knowledge, the craftsmanship skills and the budget to assemble an engine with 4-digit horsepower output, then assembling a chassis to handle that power probably would not be a challenge.

So, will capitalism be the death of knowledge?

I lived in the Los Angeles area (Pasadena) in the late 1990's. Then I was forced to move to Ohio (job transfer). I wish I could move back!!! Let's examine the complaint about the high cost of housing in California. OK, a low-end 900 sq ft dilapidated house in Pasadena costs $350K, while a decent 4-bedroom house in Dayton, Ohio costs $150K. Dayton sounds like a deal, while Pasadena sounds like a ripoff, right? But consider this: The Pasadena house cost $250K in 1998, and will probably cost $450K in 2010. The Dayton house cost $140K in 1998, and might cost $160K in 2010. Meanwhile, you will pay $2500/yr in property taxes in Dayton, and maybe $4000/yr in Pasadena (only slightly more, for a much more expensive house). And when it comes time to sell, the house in Dayton will sit for several months on the market, while the one in Pasadena will sell in a week. So consider the real cost of living - the total cost of ownership over the long term. In that regard, the lowest cost of living is in Los Angeles, the SF Bay area, Boston, NYC, and Washington, D.C. The highest cost of living is in the Midwest, the rural south, and the plains. .... Not meaning to touch a nerve, but going back to the first post in this thread - making $65K in Tennessee sounds like an entirely reasonable income, especially for a young guy with no dependents.

Back when I thought I’d be using a small block (around 1998) I ordered the JTR book, 6 th edition. The frame mount drawings are in some places off by about 1/16 th, as already mentioned. As-drawn, some of the bolt clearance holes are maybe 0.030†off from the listed diameter. But I just used the listed dimensions, some calipers and a machinist’s scale, transferring the dimensions to sheets of aluminum (I used 6-series aluminum at the time) - at it was straightforward. A couple of years later I realized that I wanted to use a different engine, and mount it directly to the frame rather than to the steering crossmember. Most of my engine mounts ended up in the trash.

Mike, If you were to add up all those tons of gravel, concrete, aggregate, dirt, and sand - how many tons would that be? Imagine, adding up the total weight of your garage project, then dividing by the total hp of all of your car projects - what would it do in the quarter mile?

I can personally attest to the repair drawbacks of cast iron heads. After spending something like a year porting my cast iron heads (OK, I’m slow and lazy), I finally took them to the machine shop for new valve guides and seats. First, the shop pressure-tested the heads to make sure that there were no cracks. And indeed, the heads held the standard 30 psi (or whatever their test pressure was) without any problems. After pressing in new guides, the pressure test was repeated. This time, one of the heads failed – it had hairline cracks across two combustion chambers, emanating from the vicinity of the valve seats. Welding the cracks was not an option. So, in the trash they go. That’s a year of porting, plus the cost of cleaning and pressure testing the heads (the machine shop did absorb the cost of the rest of their labor). If you buy a crate engine, and subject it to sufficiently benign use that it won’t need to come apart for years and years, the cast iron heads should be OK. But the more you tinker with those heads, the more the aluminum heads become the better choice.

Thanks for the links, Grumpy. Isn't it amazing how much more difficult it is to find stuff for big blocks than for small blocks. Of course, the size of the market might have something to do with it.... When I first got interested in V8 Z's (mid 1990's), 350 was the largest common small block size. 400 blocks were out of fashion (with a lingering bad reputation from the 1970's) and 383's were still pretty rare. In the big block world, a 454 was still considered a "big engine". Now small blocks over 400 cubic inches are common, and "serious" big block builds begin at 496. If I were doing it all over again, I'd get a 406 SBC. It's hard to beat the torque-to-engine-mass ratio, even if the heads flow less than their big block counterparts, and the combustion chambers have inferior shape. When contemplating a big block build, it sometimes seems silly NOT to build for > 500 hp and a 3500-4500 rpm torque peak, given the entry price of even the low-end aftermarket components for big blocks. But then I remind myself that the original reason for going BBC was for smooth throttle response and low-end tugboat torque.

Mike, What about this scenario: limit the Vette to bolt-on-type mods, which don't take it off the road for longer than one weekend at a time. Keep it as the luxury daily driver. Build one of your Z's for "svelte and fun" daily driver duty, with the objective of getting it on the road soon, rather than building the ultimate Z. Once that one is out of the garage and proudly in the driveway, plug away at the track Z. Perhaps this "divide and conquer" approach would be more effective than trying to tackle 3 projects at once (or was that 6 projects at once, counting your Mustang and your kids' cars?)

Kevin - Quote: “...not so simple as it involves a Crank Angle Chart.” Actually, this is pretty simple – it’s just the crank-slider model. Sophomore engineering Dynamics class. Quote: “ ...peak power numbers will continue to rise or fall in the rpm range based on the point in time that your airflow goes supersonic.” This is not true. The airflow in the intake tract is NEVER supersonic. With a large enough pressure difference (around 8 psi at standard atmospheric conditions, for isentropic expansion; you’ll need an ever larger pressure difference for the real-life conditions) the flow will be choked (sonic) at worse. For it to actually go supersonic, a converging-diverging nozzle is necessary. Careful flow measurements in actual running engines have shown that the maximum instantaneous velocity attainable inside the intake port is limited to a Mach number of around 0.5. Jim McFarland’s articles (“Performance Professor” on the web, former Hot Rod contributor) point out that about 240 ft/s (about 0.2 M) MEAN flow rate is a good practical upper bound for flow rate at the peak torque (peak volumetric efficiency) point. Heat addition (which happens as the flow goes toward the combustion chamber) does result in an acceleration. Total (stagnation) temperature is increased, which for a calorically perfect gas in subsonic conditions will tend to drive the mean flow toward sonic. Of course, an air-fuel mixture (with trace water vapor and combustion products from reversion into the intake) is not a calorically perfect gas, so the equations of motion have to be integrated numerically to arrive at the “proper” result (simply put, the constitutive equation for anything but a calorically perfect gas is too complex). The full answer comes from integration of the Navier-Stokes equations – for multiple species, with the “appropriate” turbulence model, and proper description of inflow and outflow boundary conditions. Specific models have been developed for internal flows, but they’re basically just educated guesswork. Commercial CFD houses such as Fluent will sell you a software package that attempts to calculate this, but it’s still largely voodoo mathematics – which they will themselves admit. Characteristics (infinitesimally weak rarefaction and compression waves) move at the local drift velocity, plus or minus the speed of sound. So in a coordinate frame relative to the local drift, they are actually sonic. It is management of the characteristics – understanding their geometry in an x-t diagram – that’s responsible for phenomena like ram tuning – but that’s another topic. Quote: “3) When the sound barrier... occurs at 0.55 to 0.60 of the speed of sound”. The statements about sound barrier are not accurate, but you’re right that the practical “speed limit” inside a port is around 0.5 of the local speed of sound. Quote: “LPV = (0.0353 x RPM x S x B^2)/CA” Well, if CA is an area, then the units for LPV come out to velocity, not volume. Quote: “Your intake manifold’s cross sectional volume needs to be 0.80 of your LPV of your cylinder head’s intake port cross sectional volume...” “Cross sectional volume”? Perhaps you really meant “cross sectional area”? Quote: “CA = ... = 1.93 sq. inches” Using your formula, the units for CA now come out to a length cubed per unit time – in other words, a volumetric flow rate – and NOT an area. However, consider the following: we want to relate the engine’s airflow needs to port cross sectional area and port averaged velocity, right? The engine ingests air only when the intake valve is open. Since we’re talking about port velocity and port area, and have left the valve curtain area outside of the discussion, we need to make some assumptions. Ideally we would calculate the area under the curve for the valve opening event (if we had data from the cam manufacturers on valve opening amount vs. cam angle, and typically we don’t). That area is conceptually equivalent to holding the valve open at a larger, constant lift, but over a much shorter duration. That larger lift would give a valve curtain area larger than the port cross sectional area. Calculating the right equivalent duration is difficult, because it’s not enough to consider steady-state effects; we need to consider unsteady gasdynamics. But we’ll guesstimate. My guesstimate is an effective “duration”, for a street cam, of around 70 degrees, or roughly one fifth of a revolution. An experienced engine builder will have a more accurate guesstimate, taking into account precise details of the cam lobe shape! THIS IS PRECISELY WHERE EXPERIENCE IS SO IMPORTANT, and theory is insufficient! Anyway, to continue – a V8 with 460 cubic inches at 5000 rpm (2500 intake strokes per minute) and 85% volumetric efficiency ingests about 1.18 cubic feet of air/fuel mixture per second. But our fictitious valve is only open for one fifth of a revolution per revolution, so that 1.18 cubic ft/s is equivalent to around 5.9 ft^3/s during the fictitious equivalent valve-open event. So let’s conserve mass: volumetric flow rate equals cross-sectional area times mean (integrated) velocity. A typical moderate oval-port head will have, as you point out, about 3.5 square-inch port cross sectional area. So we get 242 ft/s. That happens, by pure serendipity, to coincide with McFarland’s advice; meaning, if I want a torque peak at 5000 rpm, and IF my guesstimate for effective equivalent valve opening duration is any good, then the 3.5 square-inch ports are just right. But in all honesty, my guesstimate is too crude to be of direct practical use for head selection. But the real lesson here is that the main limitation really isn’t dealing with too fast a flow speed through the intake port; it’s about keeping for flow velocity high enough. Low flow velocity leads to poor intake conditions in the combustion chamber, and poor VE. At low rpm, those heads give a really low intake velocity – at some point, too low of a velocity. But how low is too low? Ah, here again we need experience! Also keep in mind that port shapes are different! A longer, more contorted port might have a higher port volume than a shorter, straighter port with a larger cross-sectional area. Port volume data, by itself, is not very useful. And unless you cut up a cylinder head on a band saw into sections, you really won’t know the internal port shape or the area at the narrowest point inside the port. Big block heads have larger port volumes that small blocks, only in part because they have larger port cross sections; they have much longer runner lengths, too.

I'll take the risk, and suggest an actual course of action: definitely get the RX-7! Why? Because you know already know RX-7's well, and it's always best to go with what you know. You already know what parts work, what parts are ill-matched, what the car's weaknesses are, what's best left alone, what needs total rework. I also think that Z's look better than RX-7's, but what matters more is which car you're more familiar with - because skills and experience (and NOT time or money!) will be the main factors that determine whether the car gets built, and how good it will turn out.

Grumpy – Thanks for the advice. One issue that comes to mind is the tradeoff between better-flowing heads and a smaller cam, vs. worse-flowing heads and a larger cam – assuming comparable port volume and flow path geometry in all cases. The advantage of the former, in my view, is the more benign valvetrain dynamics. Also, as the instantaneous valve curtain area starts to approach the size of the port cross sectional area, flow rate begins to really taper off, in which case the difference between static (flow bench) and unsteady (in the actual engine) flow data gets even larger than “usual”. So, what I’m really asking is, why the recommendation for Brodix heads, which have among the worst flow bench data on the market, and a relatively large cam (0.610” lift)? BTW, my comment about diesels was mostly figurative, to stretch the point that my preferences lean toward the absolute opposite of those who need or want an engine build that emphasizes high-rpm hp over a narrow rpm band. Kevin – I do value your contribution to the discussion, but would like to mention that elementary arithmetic isn’t always the best avenue of advice. There is a tremendous difference between theory and practice. Lack of a firm footing in the workshop – that is, the practical experience – does not imply naivete in basic engine theory. Practical choices for what to buy are especially difficult in today’s market, where so many similarly-spec’d and similarly priced products are available, and every manufacturer makes great effort to tout his product as superior. And as Grumpy noted, amateur software simulations and paperback textbook rules-of-thumb have their limitations. Two-phase viscous compressible flow with unsteady boundary conditions and curvature that makes the quasi-one-dimensional assumption inappropriate is, I think, a complex enough problem that even good familiarity with the theory is of minor help with making practical choices. So, I am looking to duplicate, as far as feasible, an existing engine build. Those peanut port heads, by the way, are history - they got cracked during the process of pressing in new valve guides.