Hey guys! I just purchased a 90 speed density TPI setup off of a 305 GTA. I know that the intake bolt holes are slightly different. What do i have to do to make it work? Also, should i just swap to L98 heads? I want about 275-290 RWHP. What all should i do? thanks for the help! Im looking forward to the new TPI!

--Steve

 

i just asked this question, and noone answered

 

Angle out/clearance the center bolts on each side and it should bolt up just fine.

That kinda rwhp is going to take some mods.

Full exhaust/cam/intake/etc.

Look around here, mnay different ways to achieve it have been done and sorted out.

later
Jeremy

 

I'm doing about the same to my 91 GTA. I'm looking to get about 350 fwhp with about a 20% loss in drive train equals about 280rwhp. This is what I'm doing to get there, stock 91 block,AFR 195 heads,Accel intake and runners,stock plenum gasket matched with some polishing, TPIS zz9 cam, AFPR, Hooker 2055 header and y-pipe, hi-flow cat, 3 pipe, programmed chip, 24lbs SVO injectors,airfoil, stock TB(maybe bored to a 52mm),2200 stall converter,vette servo and of course some fine tuning. I have to stay emissions legal, so I'm losing some hp there.

 

Some people hate when this gets suggested, but a small nitrous shot would jump you right up to the 300 range with minimal work. As long as the motor doesnt have like 200K miles on it it should be ok. Also, what year older 350 is this '90 TPI going on?

 

yeah i was thnkin nitrous. Its a mid-late 70's 350 4Bolt main, with about 70K on it. casting number 3970010.

 

isnt it just the intake manifold and heads that are different? the block doesnt make a difference does it. like if you want to run 87+ style centerbolt heads then u must use a 87+ manifold cuz its bolt holes need to line up with the heads.

but to use old style heads.. then u must modify the 90 intake manifold.


for your goals of 270+ rwhp.. you should have just bought a plenum and computer harness with all the sensors if you could find it seperately. cuz to make that power without boost or nitrous.. u need to upgrade the base and runners anyway.

 

Yea, the block doesnt matter, its the heads that match the intake. I have an older 4 bolt main block with my '88 centerbolt heads.

 

ok. Well Which base should i buy? i was looknig at that edelbrock piece, is that any good? I am trying to buy some L98 heads, and L98 camshaft. Or should i just keep my stock camshaft? I was looking at the corvette aluminum heads, i can get then for about 300/pair. Thanks for the help guys!

 

Swap to L98 heads, or aftermaket.
If you installing it on the '84 You'll need the '90 ECM, and harness.
The '90 ECM may have a VATS module, so you'll need a chip with VATS disabled, or reprogram the one in the '90 ECM.
L98 cam is a roller, your block isn't made for a roller cam, and retrofitting is expensive.
Some Corvette heads don't have EGR passages, if you need EGR and use these heads you'll need the matching TPI intake, and plumb the EGR gases from the headers to the back of the intake.
Look here for more info.
http://www.chevythunder.com/

 

I looked at the vette heads but I had to pass on them. I have to stay emission legal and the vette heads don't have heat passages and I didn't want to do all the extra plumbing to make them work with emissions. If you don't have emission get the vette heads casting # 10088113. They also have angled plugs which could give you problems with headers and plug wire clearance. TPIS will rework your vette heads for $1250 exchanged. If you buy a set for $300 you will have $1550 into them and still won't be as good as a set of AFR,Trick flow etc. and those will be about $950-$1350 NEW.

 

ok, i have a similar but different question. currently i have an 86 lb9 and i am planning on swapping in a built l82 corvette motor. will my tpi bolt onto the older heads?(i do not have centerbolt valve covers)

 

yeah it should.. 87 up was when it changed over



as far as bases... TPIS bigmouth and Superram base are the best... the edelbrock is nice but its ports arent too much bigger than stock tpi. the bigmouth is just the edelbrock base but ported out already. for the price i'd go edelbrock and port it myself or just go superram base. TPIS is nice but to me is overpriced. try on ebay, u can find the best prices on new bases. every once awhile u'll see a big mouth or superam base new for 369-389