Intake questions

[Guest gtmattz]

I currently have a 1968 327 sbc, I have been planning on getting some ebay vortec heads and have been kicking around the idea of trying to go with a megasquirt EFI system with the TPI intake, will the TPI intake bolt to the vortec heads? or do i need to get TPI specific heads?

[grumpyvette]

vortec heads can phyically bolt to a modified TPI intake but it is far better to use the correct base,because youll need several modifications to the standard intakes to get them fitted correctly, vortec ports are slightly higher and vortec heads have a differant bolt angle on the center intake mounting bolts, that require intake mods

http://www.sdpc2000.com/cart.asp?action=catalog_start&catid=1460

 

but DON,T USE IT OR ANY TPI stock intake, a TPI is designed for low and mid RPM tq, a 327 is best set up as a high rpm engine, a TPI would seriously restrict hp above about 5000rpm due to restricted air flow, the HOLLEY STEALTH RAM IS A GOOD 60-70 hp upgrade with the correctly matched cam, with its far better flowing runners, and while were at it, a vortec head is not the best high performance head

if your building a high performance engine, there are heads that flow better and require far less mods to run high lift long duration cams designed for max hp in the upper rpm ranges. vortec heads are designed for max mid range torque in trucks, true they make good hp BUT... theres other choices that make far better hp/tq

 

http://www.eecis.udel.edu/~davis/z28/winter01/dyno/dyno021105/webpage021105.html

[Guest gtmattz]

thanks grumpy, the only reason i was thinking of going with vortec is because im a cheap bastard and they seem like an inexpensive route to a few more horsies. now that you have shed some light on the subject, im not sure what i want now, lol. I would like to keep this engine as a 327, mostly for nostalgia sake, but also for the high rev potential. maybe i should just stick with a 4bbl carb, I looked up on jegs and those HSR kits are WAY out of my range. I mean WAAAY out.

 

http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=109770&prmenbr=361

 

mind you that includes the engine management system, maybe if i could find just the used intake/throttle body i could maybe afford it lol

 

so what are some suggestions for a good, easy to find, head that would keep up at 6500 rpm?

 

and thanks again for the reply

[Mike C]

Not really your goal, but if you want Vortec heads and FI, the complete 96-98 Vortec 5.7 truck motor is the way to go. You should be able to get one complete meaning all wiring, accessories, and FI stuff for $800 at a dismantler. Not only do you get a little more displacement, you get the heads and hydraulic roller cam. The motors run sweet stock and would make a Z a screamer.

[grumpyvette]

gtmattz

look here

http://www.thunderracing.com/index.cfm?fuseaction=subcategory&subcategoryid=1125

 

measure your hood clearance the STOCK HOLLEY STEALTH RAM is just over 10" tall from block to top surface

IF YOU NEED MORE HOOD CLEARANCE

http://www.fasterdeals.com/vette/

this is only 9" tall and can be dropped to 8 5/8" with minor machine work

 

all sensors,throttle body, injectors, AND CPU, and wireing should be scavanged from a wrecked corvette from a donor 90-91 TPI

TOTAL COST SHOULD BE UNDER $1000-$1200. you can resell the stock TPI intake itself to regain much of the money spent on the donor corvette parts

[Guest gtmattz]

thanks again Grumpyvette, I have another question for you. My father-in-law has come up with a set of "camel-hump 202" heads (thats what he called them) for $300. Should i grab these? He says that they are in good shape and dont have too many miles on them. I am assuming that "202" means 2.02 intake valve size, which would mean better flow, which == more power, right? Sorry about all the newbie questions, but this is my first engine build. I really appreciate all the info you have posted to the forum, I've learned alot just searching for your posts and reading what you have to say.

[grumpyvette]

"the question usually goes, hey, got a chance to buy fuelie heads for $100- $500, is this a great deal or what?" Iget it alot!

thirty years ago FUELIE HEADS were the HOT TICKET

but your dealing with heads that are thirty year old technology, they will most likey need at least a valve job,new valve guides and new springs and port work, by the time you put that much work and money in those heads youll have more than likely spent more money for worse results than buying the more modern heads that have not had 30 plus years of stress,corrosion,and bad valve jobs

 

http://www.fastnuf.com/Headguide.html

 

HERES AVERAGE FUELIE HEAD FLOW NUMBERS

 

http://www.kendrick-auto.com/462_chevy_head.htm

 

heres two comon performance cylinder heads that are available today measured on the same flow bench

 

http://www.kendrick-auto.com/dart_cs_iron_eagle_215.htm

 

http://www.kendrick-auto.com/brodix_track_i__cs.htm

 

THE CAM AND CYLINDER HEADs are some of the MOST IMPORTANT PARTS ON YOUR ENGINE AS FAR AS DETERMINING YOUR HP/TQ POTENTIAL

YES THE FUELIE HEADS ARE BETTER THAN MOST STOCK HEADS, YES THEY CAN BE PORTED BY EXPERTS AND MAKE GOOD HP,BUT BY TODAYS STANDARDS THEY ARE STILL LESS THAN IDEAL.

EVEN THE COMON VORTEC TRUCK HEADS CAN EASILY OUT FLOW THEM,

 

http://www.kendrick-auto.com/vortec_cs_gm_head.htm

 

DO YOURSELF A HUGE FAVOR AND IF YOU SPEND MONEY ON ALMOST NO OTHER PARTS BUY GOOD HEADS, LOOK AT THESE ENGINE BUILDS

 

http://www.ryanscarpage.50megs.com/combos1.html

 

THE ONE THING YOULL FIND OUT IS HIGH HP ENGINES REQUIRE GOOD CYLINDER HEADS AND A MATCHING CAM, I CAN,T THINK OF A MUCH BIGGER OR MORE COMON MISTAKE THAT TRYING TO BUILD MAX PERFORMANCE WHILE RESTRICTING THE ENGINES POTENTIAL WITH STOCK HEADS

a rough FORMULA/gauge to guess the hp POTENTIAL FROM THE CYLINDER HEADS FLOW NUMBERS is (.257 x flow at max cam lift x 8= potential max hp)

so if you have 225cfm= about 462 hp

if you have 260cfm= 535 hp

now your highly unlikely to reach MAX HP POTENTIAL but the better heads will almost ALWAYS SHOW that 15% or better results. on a 400hp engine running fuelie heads that is likely to mean you would have had 460hp with the better heads (15% improvement)

look over these heads

ALPHABETICAL ORDER

 

AFR

BRODIX

CANFIELD

DART

EDELBROCK

G.M. PERFORMANCE

PRO ACTION

TRICKFLOW

WORLD PRODUCTS

heads they all have better heads

[Guest gtmattz]

So, is there a reason (other than lower displacement) why none of those engine combos are 327's? I guess people go by the old proverb "there is no replacement for displacement" ? Is there some critical reason? I'm not going for some insane HP engine, all I'm looking for is 300-350 horsies at the wheel, I would like to do this with the 327, my reason may seem lame, but I really like the sound of a high revving v8, and the 327's hit their power peak at a higher rpm (so ive been told).

[grumpyvette]

not many people build 327s any more BECAUSE the 327s mostly used the older small journal cranks and rods that are not as comon now

327s normally cost more than 350s to build now

327s/331s normally DON,T make quite as much hp as a 350- 355 engine

383s cost about the same and normally make for a faster car

327s normally require a solid lifter cam,and good quality valve springs and fairly frequent valve lash adjustments compared to a 383 and hydrolic cam making MORE POWER

 

if your only looking for 350 hp your fuelie heads and 327 will work fine

[Guest gtmattz]

Cool!, yeah I would like more power, but I also want an engine that I can depend on for a daily driver, If i was building the engine for a dragster or a racecar I would probably be looking at getting a newer block and going 383 etc. Thanks for all your advice, sorry to have strung out this conversation so long, I guess I should have specified my goals initially . I guess this brings up another question, how much CAN you pump a SBC engine and still have a reliable engine that can be used as a daily driver?

[grumpyvette]

you can generally get close to about 1.2hp per inch of displacement before you start running into driveablity problems in most cars provided you gear and cam the engine correctly for the cars weight and compression, quite a bit more if your useing a supercharger,turbo, or nitrous

[Mike C]

I have a 331 in my Jimmy. It is a 4 bolt main high nickel 72 truck block and large journal cast crank. It has 1.94/1.50 camel humps on it. It ran 14.10 @99 in my Camaro with 4.10 gears and a 2800 rpm converter. Figure 275 hp at the wheels. It now has more than 120k miles on it. 80 in the Camaro including at least 100# of nitrous run through it, and another 80k in my 4200# Jimmy, lots of that pulling a 3000# boat. I did swap cams and intakes to make more low speed torque. You can reach your goals, but it will cost more than the 350.

 

I also have a 355, now in the Camaro. It too has camel humps. These are fully ported 2.02/1.6. It runs 12.7s at 110. Figure 360 hp at the wheels. The Camel humps can be made to flow 260 cfm. It is NOT cheap. And you are limited to 1.45 valve spring diameter as any larger seats get into water. As noted, more cost effective would be the aftermarket heads. If the 2.02 heads you can get are factory big valve heads, meaning there is a machined cut around the shrouded side of the chamber, they will make 350 hp if they are in good shape and matched to the combo.

 

A 383 WILL cost more than the others, usually by $500 minimum. But it will make more torque as well. What it won't do is use the existing flywheel, flexplate, or damper that you have.

 

My point? The 327, the 350, or the 383 would all get you what you want. If you ONLY want 300 hp, why pay more? The 350 is the cheapest way to go. For 350 hp, very reliably, the Vortec junkyard motor with 4 barrel intake, shorty headers, and a cam should easily make 350 hp, 300 or so at the wheels. It should also be reasonably inexpensive and very reliable. The bottom line is ALWAYS the bottom dollar, and the tone of your post implies that cost IS an issue. My scenario you can have a complete motor in your car for just about the price of aftermarket heads.