Hello 3rd Geners!

As a new member of the board..and as I'm beginning my research, I thought I'd start my community conversation with this question. I plan on buying a 1987 IROC-Z (my HS Grad Present) to relive my youth!

In my search for the right vehicle and in my planning stages, I've been reading about people who have built 383 Strokers and are using the TPI system for air/fuel delivery to maintain OEM look. Would love to hear your thoughts from experience on why or why not over the LS swap.

My goal is a daily driver with track ability...so YES..Independent Rear, Frame Kits and brakes are coming too!!

 

It might help us if you told us what your budget is because the rear IRS kit from Heidts is over $5K.
If it's a daily driver an LS transplant would allow you to keep up with the newer cars while still allowing for good enough manners to daily drive. But again, that depends on your budget and abilities.

 

Valid points, but my modification and fabrication skills are pretty extensive, so the rear end and/or bolt in kits aren't my fear. Its really more about the engine question I'm most interested in hearing about. Chevy sells a 383 Stroker for about $6K and generates about 450 HP with a carb...so my thought is adding a reprogrammed TPI setup to serve as air/fuel mgmt system may likely produce even more. I'm a big fan of stroker motors because of their low end power and fast reving top end HP. Plus if i'm right, the TPI setup and stroker should bolt right in including harnesses. Hopefully, someone else has thought about this and either tried or been witness to an attempt.

 

TPI intake will strangle a 383. You can get good results if you are willing to use a carb style intake. If you really want a longitudinal intake then use something other than TPI.

A basic LS3 with a cam is hard to beat for balance of drivability and power.

 

In your experience the TPI system will choke to 383 even if I use oversize runners and port the Plenum or am I just hanging onto a dream of having a stock looking L98 for no reason?!?

 

I see you're in CA too, so good luck with a smog-legal LS1 swap, if you're worried about that.

Yes any sort of long-runner TPI will choke off a stroker engine. If you're keeping TPI you need shorter runners.

My site at www.facebook.com/socaltpi/ will show you pics of what I've done with a set of SLP runners to go from 319 RWHP at 4800 RPMs and 418 RWTQ, to 377 RWHP at 5800 RPMs and 390 RWTQ.

 

That's right in the neighborhood of this magazine article.

http://www.superchevy.com/how-to/eng...tpi-induction/

It's defintely going to be fun and plenty quick on the street where traction and speed is limited. But at the track it's going to fall behind at the top of 2nd gear when it runs out of breath compared to other engines. It doesn't have to be that way. It just is because it's got a TPI intake.

 

Yeah that smog state thing....severely limits possibility

a stroker sbc will likely cost more than finding a low mileage ls1/2/3 maybe. But theres alot of swap stuff to do with ls that adds up.

 

It would still help to know your budget.
If you are in California and have deeper pockets the GM Erod crate engine is labeled as a 50 state emissions legal LS crate engine. Easily enough power for the street with that engine.

 

A TPI and anything other than the stock 5.7 is a bad idea. If you want the OEM look, freshen the 350 and leave it stock.

If, OTOH, you want plenty of power for not a huge amount of $$$, go the LS route, either a crate engine or one from the junkyard with a cam swap.

 

Are these numbers typical build numbers? I'd like to keep the engine bay looking original but not have a dog!

 

Well...in my infinite wisdom...I thought by changing the block and programming I can at the very least keep it looking stock with 425-450 HP under the hood. The LS swap is intriguing, but I fear I'll be unhappy with the look! My goal is as close to original looking as possible with a fun trackable and daily driver ability.

 

I agree with QwkTrip's recommendation and the motor in this article is what I would do. And that engine will make power. But if you are willing to make one mod, which is go with modified siamesed SLP runners, and a worked over lower intake, you will make high end power. Reach out to Dyno Don and see if he will whip you up a custom intake. With the exception of the runners, it will look stock. I know the stock runners look cool but even with the larger bore TPIS stuff, the intake ports are just way too long for high flow horsepower.

If you must keep the stock-look runners then TPIS is the only way to go as far as I know.

This a great stock look setup:

https://www.thirdgen.org/forums/engi...th-intake.html

But again, reach out Dyno Don 714 630-1502, he knows high flow TPI like noone else I've met.

 

TPI was engineered to operate in a specific RPM range producing lots of low-end torque and be compatible with then-current smog regulations. It's limitations preclude it from being used to make high-rpm power. Way back in the early '90s when 383 builds were just becoming popular by cutting down a 400 crank to fit an .030 350 block, I considered doing the same thing as you, especially having built a couple such (carbureted) engines for others, and seeing their potential to make at-the-time big horsepower numbers. But keeping the engine looking stock by retaining the TPI was the problem back then, same as it is today.

If you're planning major mods to the rear end (IRS) as well as big brakes (and the necessity of replacing the stock wheels with larger-diameter pieces) anyway, why not just go the full route and drop in a modern engine and trans as well?


JMO, but if the car you obtain is original and in good shape, I suggest you keep it that way. If you want to build a track car, or a street machine, maybe find a beater or a roller and modify it to your liking?


Whatever route you decide to take, good luck.

 

Just use an aftermarket TPI port it or use a superram those are legal
So its not a high rpm monster so what. Cam it for torque it will still haul azz and be traffic friendly.
No need to bother with an LS1 swap for this

 

No, I think these are healthy examples way above the norm.

 

Stop using logic on me...I'm building a 3rd Gen!

But really....Good advice and will have to decide on budget and ultimate project demands first. The words here all make sense and being out of the engine for sometime I've let the tech pass me by... The IRS is for increased handling after lowered and the wow factor as well. I definitely want the car to look stock but surprise a few on the road. When I said track, I merely meant a vehicle that wasn't the slouch it was in the 80's...

 

What the california guys have done with tpi is special. Follow 1989GTAtransam’s long tube runner intake builds. Also kevin91z above. You can have tpi look and rpm power but its not cheap not easy and all custom work. Welded bases, custom large tube runners. It certainly would be noticeable difference over stock tpi stuff

the FIRST tpi stuff is what i would consider if you want tpi. It will support more power and slightly more rpm than typical big tube aftermarket stuff you see

 

Too bad that FIRST doesnt have an EO#.
Have done some superram projects that made impressive #s and passed smog out here no problem. They were with C4s same thing really.
If hes not worried what a dyno says he can do a TPi build that will sit in traffic all day and make tire smoke when he wants. Still looks stock too. Guess the upside is he can use a cast crank and not worry about it spinning fast enough to hurt itself lol.
Friend got some Dougs LT1 shorties (EO#) and they got past the smog guy as his was an 89. Key thing was no bling under the hood. He had a bit of a rumpity cam 230/236 and it baaarely passed. He switched to a Crower 221/230 and was a lot happier with it.

edit..forgot about the erod, those are nice and legal but youre gonna spend some coin on it!