heads and cam recommendation
 

here is what I'm working with L98 TPI full exhaust. I am looking for some recommendations on a heads and cam setup and later on an intake. I am looking to be in the 400 rwhp without the intake and 450 rwhp with the intake. NO spray NO boost NO carb. this car must maintain Street manners and will be driven on the weekends through a 5spd and 3.73 gears.

I would like to keep all heads and cam components limited to COMP and RHS since I get great deals on them through my job. i understand the intake will be a different brand, but I want to get the heads and cam first.

things I need help with... im a bit lost with heads and cam specs and such. what would work the best for what I'm shooting for?

things that don't need to be included in thread... how long the 5speed will last and how quickly the 10bolt with explode, I know already they are weak.

New engine.

Couple things:

1.) What does the bottom end look like? Pistons, rods, crank? Compression ratio?
2.) Stock CR is 9.5:1. You aren't going to run a 400whp cam with that, let alone have any semblance of street manners.
3.) Who is tuning this thing?

I'd like to keep compression to 10, bottom end will be freshened up when pulled

In my opinion, you are asking a lot from a motor and induction system that put out a designed 225 horsepower. The biggest limiting factor if I'm remembering right, is the TPI intake.

Your next biggest problem is going to be tuning. You need to find someone who can tune the TPI motor, and that's going to need a chip burned. It's been a very long time, but somewhere in the back of my head I recall the computer needing to be modified (chip socket soldered in) to use burned chips but I might be mistaken about that.

With that power on tap, the five speed isn't going to live. They grenaded with alarming regularity at stock power levels on street tires when driven hard. Same thing with the rear axle.

Unless you are stone set on the TPI, you might be far better off with an LS based swap. The right 6.0 with a cam makes 400HP all day long.

Lt swap if you want to bolt your trans to it, I'm assuming it will. Prob round $4-5k for the 400+ rwhp pending a few details. Ls swap, cam only and bolt ons will get you close pending trans.

tuning is not so much an issue I already have the auto prom and do the chip burning no biggie. if 450 hp is far fetched then I can work with something less. I don't really want to do ls since I can get gen II SBC parts so freaking cheap, I don't really want to disclose pricing, let's leave price/cost for engine components out.

the stock TPI intake going to be ditched at a later date for a TPIS unit or holley piece.

at this point I'm merely thinking out loud as far as options I do know I don't want to boost if anything NOS but I would really rather be N/A

You sir have a Gen I.

If you want, try going for 375-400 at the fly if you don't want to get too deep into it.

lt1/4 is the gen 2.

You're going to spend a lot of money and be wayy behind in the power game. Lt1 will get there a little easier but there isn't much support for them anymore etc and people don't understand them for some reason. Ls is your best bet, a full bolt on ls1 in that thing with some minor weight reduction will be lots of fun and have lots of room to grow in the future with plenty of aftermarket support. And you will increase reliability and have pretty good fuel economy along with great street manners. The money you save now on your parts discounts will end up costing you in the long run.

my bad gen I

Build a 406.

is inspection important?

'86 so he can possibly QQ it.

Mod motor in there.

I have some relevant experience and will give you my opinion.

450hp out of a 350 Gen 1 entails spinning the motor to a 6000rpm (or a bit more). I have a 400hp 350 at it peaks at 5500-5600 rpm.

There are two issues you have in terms of power:

1) Is the motor going to hold together at 450hp and 6000rpm+ (it probably will, but stuff happens)?

2) Will your choice of parts allow the motor to make both the power you want and be of high volumetric efficiency?

With an aftermarket TPI replacement manifold (vintage or new), 450ho is not a problem if the other parts are correctly matched.

But I've never heard of a stock TPI intake even cracking 350hp, let alone 400 or more. It comes down to the long runner design that boosts low RPM TQ at the expense of high rpm HP. No stock TPI motor makes its peak past 4500rpm, even the less intake limited 305.

In terms of parts, Comp Cams will make a cam to get you where you want, and RHS probably has a set of heads that will work too. But I would suggest just ditching the OEM TPI style and go right for a TPIS miniram - which is meant for high rpm hp. About $1,500 with the fuel rails and a new TB.

The last issue (and an important one) is the tuning of the computer for maximum power and streetability. TPI had an ancient computer with limited ability to change parameters, early ones (85 to 87 I believe) are way worse than the last few MAF ones. You can get a reprogrammed PROM, but it usually takes a few updates to get it optimal - it is not 1/100th as easy or comprehensive as late model OBDII cars to do.

Paul,

Splitting hairs but he's talking about wheel horsepower. So probably closer to 500 at the fly, if that's the units you were using.

Guess I didn't notice that.

500hp is a 6500rpm peak - or a 383 at about 6000rpm. Never going to happen with a TPI intake, but doable with other alternatives.

Paul I have to agree with you. The TPI intake is designed for tq output. You will build a tq monster but be low on the HP side. The two biggest stepping stones are the heads and intake. That is where its limited the most. 400 fwhp is possible but you wwon't get 400 rwhp. And if you do somehow the t5 won't last through your dyno pull. I would seriously invest in a t56. Its basically a bolt in with the exception of a couple things. I would also punch it out and do a 355 or 383 and definitely go with a tpis mini ram or a stealth ram for your intake. I wouldn't go to radical on the can. Remember tpi is MPFI not SPFI meaning on a tpi the injectors fire left bank right bank. Not in the engine firing order. You may want to do some reasearch over TGO. There are a lot of guys making good power over on the board using tpi in one variation or another

My stock 305 tpi made close to 350 rwhp. With a stock T-5.
(With larger injectors and blower)

I've done 400 to the wheels thru a stalled auto and some archaic computer ...... Then again, I've dumped to much money into the damn engine. lol

Putting a blower is an easy way to make power on a TPI car - easier to tune for some also.

Problem is that the TPI even with a supercharger is still going to exhibit the same power curve, although the TQ is going to be pumped way up (as is the HP).

Having seen quite a few 350s with Paxton and Vortechs barely making it to 350 fwhp in street trim, I'm curious what your car ran and what "stock" means...

Only slp runners, 58mm tb, larger injectors were on the 305. The motor was not touched.
T-5 only a clutch. Was not rebuilt.

i have done some research on TGO (86iroct5) and got ripped apart on my question. what everyone seems to be missing is the fact that i WILL do the intake, i dont need help with that. i KNOW the rear and trans will need to be bolstered. i need help with cam/head specs to get me near my goal, that is where im not so knowledgeable. which is what im not really getting help with.

i dont need people to tell me its impossible to make 1.25HP per cube on a 350.. im not a stickler for numbers, id be fine with 400 fwhp. i was kinda just thinking out loud with my original post if its not feasible thats ok im all ears to what is.

i dont want power adders period. i dont like them if anything it would be nitrous but i dont want that

/rant (not directed at anyone)

i have a MAF car so that is a plus. i am lost with computers but have a good friend who burns chips and makes tunes and is pretty good at it (made a tune for his boosted MAP 305 TPI). im not really worried about the tune.

lol nick. thats not to suprising. tgo is a total waist of time and effort. when i use to have my thirdgens i got more help on a 2nd gen website then i could get on tgo.

i go on there more for laugh, though the search function is pretty decent. most of the recent posts are BS