dr_hunt

Ok, your into the world of cam timing. Small heads are a restriction much like too small a carb or restrictor plate racing. Larger cams will help extract power but you will never see the full potential of the cam. Solid roller in the 250 to 260 duration range at .050 isn't really that big, kind of like a 240 duration in a solid. The attributes of the roller cam are significantly different than solids or flat tappet hydraulics or even hyd rollers. They sound mean but pull from low rpm's. Pay close attention to intake lobe centerline and LSA. For the street 108 to 110 will give you a broader rpm range. Less than that give more mid range torque, but narrows the rpm range and probably won't work that well with your heads. I run two solid rollers on the street, one is 267/276 @.050 .640 lift 104LSA in the 406 and 250/260@.050 .640/.666 108LSA in the little 350. Both have AFR 220 CNC heads, Little one 13:1, big one 14:1. On the engine dyno the little 350 made over 400 lb-ft of torque from 2000 all the way to 7500 with a peak torque of 558 at 5300 rpm. A 250 duration on the intake side will be a stump puller pulling hard from 3000 up. Probably run out of breath with your combination at 6000 or so. Flow numbers in the .3, .4, and .5 range are more important since the valve hits these figures twice during the valve opening event rather than focusing on the peak flow numbers at peak lift. AFR's kick some butt as do the Edelbrock victor jr's. Keep in mind that 20 years ago your heads would have been top of the line. Depends on money, if you don't have any, run what you have, I would! Go with a roller and you'll never look back except to see how far you wasted the other guy!!! David

A buddy of mine has a procharged carb application on a 350 fit into a ' 67 chevy 2. Hydraulic cam, .480 lift, TRW turbo pistons, eagle rods, steel crank, Dart Pro 1 alum. heads, victor jr. Holley 650, electric pump, 1-1 boost referenced regulator, TH350 with a 2500 stall. 10.02@137mph on 10 inch DOT ET streets at 6000 feet elevation with 17psi boost. Car weighs about 3000lb in race trim with driver. Should be a real screamer Z if you could get it to hook. The procharged motors launch relatively easy provided you don't have alot of stall in the converter and unleash fury at about the 60 foot mark. David

The truck blocks are not sought after for HP builds cause they won't accept stroker cranks. They will accept longer rods however. Aftermarket blocks come with either deck height and one even taller than that. The truck block isn't a sought after piece. I have several 427 truck blocks, they are 4 bolt mains, but you can't stick stroker cranks in them without major machine work.

Sounds like a classic sick quadrajet. This is a very simple carb that few people understand or comprehend. Correctly built and tuned it is a fine performance carb for the street. A completely stock rebuild should get you to where it starts and runs without touching the accelerator pedal or pumping it once to get it started. If you are going to build it yourself disassemble it and completely immerse the carb parts in carb cleaner for several hours or longer depending upon condition. Rinse thoroughly and blow all passages with air. Make sure you remove the air valves in the base plate and blow those as well. Some come sealed, which can still be removed if you drill out the plug. Standard settings on the air valves is 3.5 turns out from lightly closed. Set float level at rebuild specs and use a brass float. Since it is not on an original engine, tuning is going to be required. Adjusting primary metering rod height is critical for cruise enrichment as is the proper primary metering rods. Secondary cam, rod hanger and rods need to be selected based on the plug readings and any hesitations, bogs, etc. The secondary air valve is controlled by a spring that is adjustable. I think it is 1 turn for SB's and 1.5 turns for BB's, but that is stock and you can adjust it from there to remove stumble caused by premature opening of the secondaries.

alot of the options on 67-69 z28's were dealer installed options and were never factory installed. There is little if any difference in the heads in terms of performance. Chevy claimed 15HP increase at 7K with the spark plug angled, however production heads vary so much in air flow, that small of an increase is not something to bank on. If the car was "show quality" and going to be judged, it'd get knocked pretty hard for having the wrong heads, whether or not they were dealer installed or not since they are the wrong year. Watch out on those extra set of heads, are they usable?? Cracked? Excessively milled??? Valve guides shot??? Bolt holes stripped??? Do they have the correct 2.02/1.60 valve size?? Have they been rebuilt too many times and have the valves sunk into the seats excessively?? Were they original heads with screw in studs and guide plates or were they modified?? 186's with 2.02 valves, screw in studs and guide plates are very very rare in original form, they didn't make many and all were on the DZ302 or the vette engines.

The angle plug heads are not original. the xxxx186 head castings never had angled spark plugs. That head is either the angle plug corvette head, 1970 through 1972 or it is a GM bowtie head of even later production.

zeeboost, I've had three failures of speed pro hypers in circle track engines all wrist pin related. One the wrist pin actualy broke in half between the rod and piston boss on one side, scored that hole and had to sleeve it, bent a rod, causing the adjacent rod to be replaced due to bind and discolor the big end. Also had evidence of the wrist pin severely bending prior to breaking. On two others the wrist pins bent causing binding of the piston and rod creating severe scuffing on the skirts. Speed pro made good on the broken pin, by replacing parts. Big whoopie. On the bent pins, I was told by speed pro that they must of hydraulically locked. This is funny cause both engines were running and were torn down for a freshen only, bad leak down tests, and two pistons in one engine and one in another were scuffed pretty bad and had left aluminum on the cylinder walls which was causing blowby. Both engines had no reports of any problems of any kind, reputable drivers I've known for years, both were bushed rods, in both cases pins were bent .002 to .005. I have no reason to doubt the drivers, neither engine was there for a "comeback catastrophic failure" only a freshen. Since then I don't use speedpro hypers and I haven't had that problem since, so at least in my mind it is my opinion to go with KB's when doing hypers. David

First of all stock rods are not weak, besides your not running alot of compression, turning crazy rpms all the time or spraying NOS right? I recommend polishing beams to look for cracks, mag them, install arp bolts, resize them for max crush and let em fly. Turn stock crank 10/10 or 20/20 on the high side and leave it, balance it, it'll work. Pistons look like speed pro hypers, kind of iffy on the wrist pins IMHO. I wouldn't do total seal rings for the street, spend money on heads instead. If it had excessive blowby then total seals won't work even if you hone it. They only work with a fresh, true, round perfectly straight bore, even their own literature states such. Go with a KB hyper, moly rings, get some heads, polish the beams, arp's, arp head studs (clamp better and give a better ring seal if you bore and hone with same). HV oil pump, steel sleeve shaft, block off filter bypass (sounds like it wasn't done before resulting in scoring of journals/bearings). Go with new spings, lifters, retainers, locks, cam, most failures are here anyway. The rest of the normal stuff as well. Check harmonic for elastomer failure, cracks, etc. run new one if needed or upgrade. If you really want it to last, baby it like 'ol grandma, otherwise it's always rolling the dice as even Nascar looses engines now and then and they are 80K apiece! David

I have both my 690HP Monte SS and my boys 650HP Z insured with Allstate. They are both specialty cars and when I want to drive them I call them and tell them when I'm driving. Insurance for the Monte is $250/year for full coverage and the z is $200/year for full coverage. No restrictions on drivers, mileage. I drive them on the street on weekends and sometimes during the week in the summers to street spank, i mean race the locals.

Well, been there before, but way worse, had a kid with mine. My boss told me to get rid of her as she would destroy me, I didn't listen, I ended up in jail, lost my job, cost me 50K in custody battle legal fees, only to have visitation with a wonderfull son who I'm building a hybrid z with and dealing with a psychotic mother witch weekly. Mine's 34 now and never had a job, never will, lies constantly, makes up stories for sympathy, etc, etc. Dude, as wonderfull as she might seem on occassion, she's not, even you are having doubts, take it from some of us, you ain't the first, you won't be the last to experience something like this, but take my bosses advice since I didn't. Leave her, find a rustbucket z, spend 100K fixing it, run 8's, but whatever you do, leave her alone, your attracted to a self destructing woman who will destroy you or anybody that is associated with her!!!!! women, can't live with them and it ain't legal to shoot 'em!

377 if it has .030 overbore. Rod length doesn't affect displacement, only improves rod to stroke ratio, which in turn adds some benefits like reduced side loading on the piston skirts and slightly increased piston dwell at TDC.

I'm going to throw in my 2 cents worth, probably not worth much, if that. Many of you members are probably too young to remember the 327 in it's heyday. Most of you have probably never owned one. Ditto for the 283 or the 302. Many a 350 was left in the dust by a 327. Remember Grumpy Jenkin's 331 pro stock '72 vega turning 8K plus running 9's. Nascar and other racetracks are the testbed for what we simpletons end up with from summit, jegs, etc, etc, only down the road. Why is it then that Nascar is using SB2.2 with 4.125 bore and 3.25 stroke with Honda rod journal sizes, turning 9500 rpm for 500 miles? Because for racing it works better than anything else. High rpm isn't what kills engines, it is valve train harmonics and part failure that kills. Of course there's always stupid stuff that kills, but by and large, part failure is the main problem, be it valvetrain, piston, wristpin, rod, whatever. Everything has limits, but if it is built right it'll work, if it isn't, simply, it won't. If you want to turn 7500 rpm then build it for that, but don't take stock parts in a small cube engine and try to turn it past it's limits. Rev limiters, stutter boxes, whatever you want to call them are a good thing for the absent minded of the day. Set limits and stay within them and no matter what you do, if it moves, sooner or later it'll fail. That's why nascar has qualifying engines, race engines, etc. and all are always new parts, not one race old parts. The law of averages will catch up with you sooner or later, and 500 miles is not alot of miles, just hard ones. Best street engine? Whatever your mind will ponder and your pocketbook will let you assemble. Best all around?? Subjective question littered with personal preferences. But there's nothing like the sound of a sbc going above 7K, sounds magical, mystifying and wicked. An old man told me once, that if I was willing to part with something, sell or trade it so I could buy something else I wanted, that I'd be able to experience more without breaking the bank. Nothing you build will last a lifetime, only for a few years anyway, so build a 327, 302 or something like that, run it and sell it or trade it, then buy or build a 406, 421, 434 or something like that. I've built alot of 434's for circle track that turn 7800 all night long, all season long. I've built and owned 283's, 302's, 327's 350's, 377's, 400's and one 434, from mild to insano. Liked them all! I was way, way, way, way impressed with the 434 in terms of seat of the pants ride, scare the shit out of you acceleration, due to monster torque and HP. Then again the 327 never says never and keeps pulling and pulling like the energizer bunny. Another note, I've got 10 small blocks in my shop, including a dart block, several aftermarket cranks, carillo, eagle, C&A rods, etc., etc. There is something to be said for aftermarket blocks like world or Dart, but really only when building monster cubes in the SBC. By the time you deck it, align hone it, bore it and hone it with deck plates, clearance it for big stroke and rods, install deck plugs, hard block, etc, etc, you have 1200 in it already. If you have to tunnel bore the cam, forget it, go aftermarket, it is a better product and will at the very least, give you better ring seal. You 400 sbc guys know all about that already don't you? David

Cool guys, that's great. If I'm low enough I can avoid the windshield box but then I'm really too low to tie to a cross bar under the dash and then it really doesn't add that much support to the front frame like I think it should have for 650HP engine. Your pics are a big help. Question how did you weld all the way around the lower door bar where it intersects with the passenger side halo/A pillar bar? It looks really close to the body. David

Also it may be a good idea to back off all the rocker arms so the valve springs that are compressed don't take a "set" and loose tension. Another good idea is to rotate the engine periodically.

Don't put a resistor anywhere in any wire on an HEI, they require a full 12-14 volts! The negative post on the HEI terminal cap is for the tachometer, not ground. Personally I wouldn't wire the ignition and fuel pump in the same circuit for fear of voltage drop to the internal coil of the HEI. Separate circuits are also easier to troubleshoot as well. Don't know diddly about z wiring, can't help with anything more. David

I've never heard of someone "maintaining control" and possibly spinning, flipping, catching air sideways and taking off. The force of the air on the front of the car exceeding the traction limits is an impossibility at even 200mph plus. Think about it, the Cd is around .35, frontal area is what, 19 square feet if that, air density at STP, using dynamic mu for asphalt and a normal force of 1500 lb on the rear tires (2), do the math.

Stuck lifters won't cause loss of oil pressure like that. It is most likely a rod, if it were a main then the rod is the last to oil so it's gone as well, probably both. Going to need to turn the crank, and resize the rods, better to do it right than wish you did later when it doesn't work. Since your there and installing new cam, better have new guides and valve job done. Better check for proper spring pressure and retainer to guide clearance with the new valve seals in place. If cylinder walls have excessive taper then bore it and install new pistons. Well, since you've done the whole engine by now, might as well stroke it, puff it, spray it and whatever else your pocketbook will allow.

If it wiped out a cam lobe and you didn't do a complete engine tear down then that is why it's doing what it is doing. Definately, got a plug or restriction somewhere. It's a wonder it didn't seize.

Well, the real way to tell is to have them pull the pan while you're there, then you could really see what's what. Other than that if the pan is on look at the rear flange of the crank, if the parting line is thin, say .125 then it is a cast crank, if it's .250 or so, then it's forged steel and likely they are telling the truth. Pull the valve covers, check the casting numbers. You know, it's your money, better check it out first before laying down hard cash.

Food for thought. I run a 406 sbc in my 3800 lb monte SS, cola steel crank, dart block, eagle h beam rods, lunati 14:1 pistons, comp roller 260/267 @.050 and .645 lift 104LSA, AFR 220's milled to 66 cc, victor "E", C&S aerosol billet 900 carb on alky, th400 w/ 4000 stall, 9 inch with 4.11's detroit locker, SSM lift bars and run a 26x13x15 M&H slick. Foot braking leaves line at 4000 rpm with the left front tire 6 inches in the air (got pics), 1.54 60 foot times, shift at 5800, traps at 6200 to 6300 results in a best to date 11.66@115 at 6000 feet elevation, so you don't have to wind it tight. Build torque, HP comes along for the ride! About ready to fire the 260z for the first time weekend after this, 350 stock 4 bolt block, Eagle steel 3.500 stroke crank, carillo h beams with CARR bolts, JE 13:1's, AFR 220's milled to 66cc, edelbrock scorpion, C&S aerosol billet 800 carb on alky Crane TR250/260 .600/.625 108LSA, powerglide, 5000 stall, 9 inch 4.56, detroit locker, QA1 coil overs and ladder bars, 29.5x9x15 slicks. Hoping for 10.50's off the trailer at altitude, should run in the 9's down at lower altitude somewhere.

The stock 400 crank in my experience is good to 400hp reliably, beyond that I've seen them develop cracks when used in circle track engines. Street might be good to 450hp. I wouldn't recommend spinning stock rods, either 400 or 350, even with ARP fasteners, polished beams and the works to 6500. I've done it, seen it done and seen them come un-done with disasterous results on the rest of the engine. 6K may be a more realistic redline for that type of bottom end. If you are going to use the stock crank you should consider internally balancing it regardless. Better yet, is to go aftermarket with a crank like a 5140 or a 4140 crank from SCAT or Eagle, get some rods as well, good insurance. The 4340 cranks are race oriented and handle more hp, but the 5140's can be had for $400 and work fine. Cast pistons won't work for long above 6k cause they can't handle the stresses, hypers good to 7k, forged good everywhere, so take your pick. For street it is better to have tighter piston to wall clearance, helps prevent piston cocking in the bore which improves ring seal and wear.

Well, I have to bite on this one. Valve seat face needs to seal, period end of story, that is why quality machine shops do a vacuum test on rebuilt heads. Typically at least a 300 grit stone will get you there, that is what most valve resurfacers have if not finer. Lapping valve in is recommended for valve seats done with the old "stone's". When a valve opens and closes several thousand times it literally beats the seat and valve so that it is mirror like in appearance. Backcutting the valve face in the exhaust will net you a 10HP gain in a v8 if done right, since it has to complement the valve seat angles. Radiusing the valve seat between the seat and the bottom of the valve is also a good idea, good for another 2- 4 HP. But if your looking for horsepower there then you have already done every other trick in the book and you'll never know or feel the difference anyway. Ol' Magnum has it right. Swirl polished heads are great for race engines, but with carbon buildup on street engines, the benefits don't last long. The actual stem is usually chrome plated for wear resistance. If they have more than .001 wear, junk 'em and go new or they'll suck oil, carbon up and wear out the seats so fast it'll make you wish you did it right the first time. Never, never touch a stem with anything that removes metal. So that leaves you using a rag.

Yup, I bought it on the internet for my Monte SS race car, but can't remember where, meets SFI spec's and the whole nine yards. Stuff is way way way too expensive. I think it was $80 for a 6 foot piece. It doesn't wrap arount the roll bar either just attaches to it on one side, Bought that, went to NHRA tech inspection, they said I could of used the cheap stuff that everyone else uses. The stuff isn't very durable if you rub on it getting in and out like I do, starts coming apart.

ahem I haven't heard anyone mention roll bar padding?...! It isn't legal to race without roll bar padding installed within 12 inches of your head anywhere, so why is anyone concerned about hitting your head on rollbar with padding versus the interior of the car? Anyway just an observation. I couldn't find a cage worth a hoot and they all take fabrication and welding of some kind or another so, I went the other route on roll bar. I got on EBAY and bought a $400 bender (delivered) and a $100 dollar tubing notcher with roller bearings (delivered) and $150 worth of 1-5/8" .120 wall pipe. I know that is alot of pipe at $1/ft, but I screwed up alot, but I still have 30+ feet left over. I'll take some pics and email them if anybody wants to see them, I tried hard not to interfere with driver comfort and I'm really close to the roofline. I'm 6'1" also and I fit fine. It did limit rear seat travel by 2 inches, but that's the way it goes. Had to remove windshield to finish welding HALO bar and had to remove rear quarter windows to weld main hoop to rear bars. Also had to build chairs on the floor next to the wheelwell behind the seat to attach to. Mine is more of a NHRA type 12 point cage that goes through the dash and down to the floor, but you could not go through the dash. I just wanted to be as close to the A pillar as possible to aid entry and EXIT from the car. You never know, you might want to get out rather sooner than later. Just an opinion and insight on why I went the way I did. And just so you know, it's really easy once you screw up a couple of times and figure out how to bend it right where it'll fit.

Ought to be real streetable and sassy. Go for it. Is it going to be efi or carburated? Remember the one piece rear seal cranks take a different flywheel/flexplate. 305240 is right, your building it all wrong. But so you don't have to bother with shipping, give me your address and I'll come take that junkola off your hands and haul it to my garage, eh, the dump, yeah, the dump. David