Hey all. First off I don't have a 3rd gen right now, but I've owned two in the past. I'm going to be getting another one soon and this is what I plan on doing.

I'm going to look for an 85-87 Iroc with a TPI 350 to start. I want to build a 383 with 202 heads, all roller setup and forged internals. I'm looking at atleast 500hp to start off with. Will a TPI with a ported Plenom, SLP runners, and larger injectors be able to handle this? Also I may want to S/C it later.. we are talking 650hp here. Is it possible for TPI to handle this?

Thanks
Phyte

 

I think you can get an L98 to about 400hp on the motor but beyond that you will need an LT1 style input (like a mini-ram) since HP is better built up top and TPI is a "torque" builder (bottom end). With a 383 the mini-ram should be a good intake.

 

I don't see a TPI making 500HP N/A. A miniram could b/c it would rev way higher, a SuperRam would with a good size engine under it (427 smallblock) and a decent size cam. Your best bet for making 500HP N/A is with a miniram and revving that crap out of the engine. Not good for the street.

If you got a 383 with a superram and good heads and cam, you could make 440-460 HP and a lot of TQ and it would be GREAT on the street. Put a supercharger on that and you would have a GREAT street car. The problem is if you build the engine for N/A, the compression ratio should be higher than if you build it for a supercharger or turbo.

 

Ok I didn't see it happening either, but I didn't know with all the mods available for TPI. My last setup was a 350 with Dart 202 heads, Erson 292 cam, TRW forged 10:1 pistons, Victor Jr, and Holley 780DP. This dyno'd at 416rwhp. The engine started making good HP at over 3500 rpm, so ya it was a really high rev engine.. But I liked it that way. Nothing like hitting 55mph in first gear

Phyte

 

Thats my delima right now.. I don't know if I should go with 10:1 or higher pistons, or go with 8:1 for S/C later on.. I will probably just go with the 10:1 and forget about the S/C

Hell I don't even have a 3rd gen yet.. I'm getting ahead of myself here

Phyte

 

If by "202" you mean intake valve size thats probably one of the lesser important parts of the head Bigger valves aren't always best. Second I agree, 500hp on Tpi of any form is a very long shot, at a 383, even maybe a 400. Bigger injectors aren't better, CORRECT injectors are. Finally 85 didn't have a 350, so dont buy one. The ecm was crap too, just something to look out for. The newer engines have the new intake bolt pattern, serpentine belts, and less buggy ecms thats what I'd shoot for. You might want to look into a miniram or LT1 intake if you want HP numbers over TQ numbers. The super ram is great for a balance and street ability but you're going to need the RPMS to hit that kind of HP numbers, probably some solid roller lifters/cam as well.

Good luck

 

Yes I mean the intake valve size on the heads. I call them that because its common to call aftermarket heads by valve size, kind of a slang(atleast thats what I've always heard). Your right there wasn't a 350 in 85(forgot about that).

What I would like to find is(best scenerio) is a 3rd gen with 350tpi and tan interior. I don't care about exterior color because its going to get a shot of Orange either Ontario(early 70's vettes), or Hugger. I'm going to strip it down and rebuild it up from almost the ground. I just want something cheap with the two options specified. Money is really not an issue as long as the wife can be convinced I need another toy

Phyte

 

Haha, you got the all time road block in your way then

Yea even from a ground up rebuild its nice to have all the pullies and odds and ends and stuff from a later model car, I dont know, maybe its location, but around here the "slang" is usually by intake runner size, i.e. "200cc heads" etc.

Good luck with your project, mines just coming back from a "med red 3 stage pearlecent" paint job, yummmmmmy

 

Could you pull off more horses if you used lets say an after market intake and siamesd runners and plenem? And possible siamese the intake manifold?

 

Yes

but still not 500hp

 

how much more do you figure? Like from between stock set up to mini ram.

 

I'm guessing that 30hp is a fair number, Its not by any means a "power adder" but it allows you to rev more rpms. So if you take your existing torque, and miniram it, you'll multiply that torque by a few more rpms giving you great hp output, and probably slightly less torque. Either way to make 500hp you'll need 383 or more CI, some SERIOUS heads, a SEROIUS cam, and something WIIIIIIIDE OPEN (like a miniram). Power adder will be your best if not only way

 

Blah blah blah, blah blah, blah blah blah.

Where do people come up with these HP 'limits' for TPI? Theres no limit, only in your mind.

"With my old setup which included a Paxton (6-psig), I dynoed at 421 rwhp."

Thats ******* car BEFORE he changed to the ATI he is using now. Thats with, um, a 305! If I am generous and use 15% powertrain loss (yea, right) thats 495HP.

HP limit my foot. I think the only limit is the person building the engine combo.

 

Well since you want to be like this....


Read how he wanted to make 500 hp

NATURALLY ASPIRATED

then wanted 650 boosted

If you think LTR tpi can hit 500hp, please by all means, show me a car doing it (not boosted/NoS)

 

No 350 TPI in 86 either, suprized this did not come up....LOL...oh and don't even start with the infamous 50 prototypes.......i don't think they ever exsistend nevermind making it to 2002. 87 was the first year for 350 TPI in f bodies....PERIOD

 

Good information guys. Its been awhile since I've owned a 3rd gen(8 years) so I'm alittle rusty.

Here's what I'm thinking about. 350 block (.60 over) forged pistons 10.5:1 or so 400 forged crank(383 obviously), complete roller setup with cam making max power between 4000-7000 rpm, a set of Dart II Sportsmen heads with all the trimmings including complete port/polish job. I've got access to a valve grinder so some bigger then 2.02 valves will go in. Miniram and the trimmings and all the other nessasary equipment needed(HEI, Fuel, Puter, etc).. I think this combo should be good for 500hp with the proper tuning.

I'm trying to sell my 69 firebird and 1992 Jeep right now to pay for the project. I was convinced in another thread to look for a 90-92 model to start with. Thanks again for the information

Phyte

 

If you don't have to worry about emissions you might want to look at the holley stealth ram. It is much, much cheaper than a miniram.

Madmax, everyone is talking about 500 HP N/A not supercharged with a TPI.

 

Good call on that


Cheap power

 

Sorry, I was just going by this quote here:

I still dont think its an obstacle that you cant go past, I think thats a bunch of BS, even NA.

 

well theorys are grand, but usually inconclusive imo...

It seems you'd be able to, but when you think about it it takes a very wild carbed 383 to hit numbers like that, but doing it all with FI and LTR's takes alot of money, alot of time, and alot of resources that we really dont have

you'd need to spend DAYS on flow benches with your head/intake/runner combinations tweaking everything

who knows, theoritically it IS possible, but likely.... I doubt it

dont get me wrong, I'd LOVE To see it done!

 

If you are talking about the Single "non-siamesed" LTRs (no Superram), then I seriously doubt 500 NA HP. If after 15 years NO ONE has yet made 500 HP (without a power-adder), there is most likely a reason.

500 HP from a Superram or Miniram is/has been done. But not LTRs. When you see all the dyno runs from the people that have LTRs, the reason is obvious. EVERYONE has a real flat HP curve starting at 4,500 RPM. HP needs revs, and the TPI system chokes the top-end. It's like expecting a MINIRAM to make the same low-end TQ as a TPI (with identical mods)...won't happen.

If you want to make High Revving HP, get to a "short runner" system or a power-adder. EVERY PERSON that has taken their TPI and replaced it with a Miniram (on a modded motor) has gotten MORE top-end HP, plain and simple. (And yes, sacraficed bottom end TQ).

To get 500 HP from TPI, you'd need an engine designed for mega-torque at 4,500 rpm. This means a big-cube SBC (434 or bigger), but I still think you may have a problem flowing that much air from an LTR setup. And when you consider spending that much money, why not just sport the extra cash for a better flowing intake.

 

One other thing... the 85-87 years may not be your best choice. Finding a 89 or later may be your best bet (not that I am knocking those years, I own one).

If you are really serious about running a motor with that much power, a lot of people on this board will tell you to get a 90-92 with Speed Density, and bypass all the MAF issues. Of course, you will have to learn how to program your own chips.

 

Good point Mike.

But in all honesty, the easiest way to make 500 HP is to get a Big Block. It's one thing to make a lot of HP from a small motor, but the Big Motors do it so much more reliably and due to their cubes, without having to be so "high strung". Then you have TQ and HP.

 

Well 500HP engines dont exactly grow on trees either. I wish I had some dyno sheets on my friends old car, because if it wasnt there it was real close to it, no miniram or superram. I've seen the timeslips, took a bunch of power to get there with a stock weight car, no doubt in my mind. I think to say its not possible is wrong, I think it is possible. What you find is at that point if you get there, you could probably get 100 more hp easy by getting rid of that intake. If we are talking about when the manifold becomes a restriction in stock form, the HP is much less than what everyone is saying, like half as much. Kinda like Nascar and restrictor plates, when you are sucking through a straw you can still make lots of power but why do it?

 

I was hoping myself to use a tpi set up and get some nice horse power gains. I don't mean the stock set up but a siamies(spelling) set up. But from what I've heard from companies like TPIS it would blow.
I just thought how great the engine looks with the tpi set up too.
Let me know what you guys think.

 

I haven't been able to find the holley stealth ram. Can some one posts some pics please?
Thanks

 

How close are stealth ram, or miniram intakes to lt1 intakes?
If you want to make a 500hp naturally aspirated 383, a lt1 would do the trick. You could run 10.5 comp ratio without detonation, and sequential fire injection makes more power.

 

I don't know about 500 HP, but maybe close. I just got my 389 CID Vortec motor. I bought the newest Comp Cams Extreme energy cam and added all the go fast goodies I could find. Desktop Dyno says 450 HP. I know, I know, let's not start on desktop dyno. I do know that I plugged in a grunchload of different cams and the best I saw was 420 hp. Then I called Comp Cams. They gave me a part number I had never heard of and I got the specs off their website. I plugged in the cam specs and voila, 450 HP 520 Torque. Nothing else came close to those numbers. Anyway, I haven't decided if I'm going to pop for a G-Tech or the Dyno time yet. But after I get a couple thousand break-in miles on the new mill and a new chip I'm going to find out what it's got. When I do I'll let eveyone know, unless it turns out to be a dog.

As far as the Stealth Ram goes I haven't seen any dyno numbers runner length numbers or any other numbers other than an incredibly low price if you don't have to be emissions legal.

 

Ive seen 90% stock topends handling 460 hp...

 

blown

 

Get an 89 TTA,
Turbo Trans AM.
It has all the good parts to begin with
200R4, Aussy rear end, 4 Whl discs.
Go get 500 HP takes a few plumbing changes, a turbo, and injectors.
Oh and some computer work.

 

Hey, no fair bringing in ringers!

 

TTA has a power adder and is not N/A, but IS a very nice car to own if you got a chance to get one. It is also 200-4R or 700R4 on the transmission ID.

 

Kdoggs, can you expound on that 460 HP with 90 % stock top-end?