NonGoggleGuy

Hey guys. Looking for some advice. I just picked up a project Fiero recently. The plan is to restore the car from the frame up, and get a blown LS1/LS6, and build it from the bottom up.

We plan to stroke it with the 383 kit, and everything & anything else that happens to come up. We also "plan" to twin turbo it after the build is complete and running, so we want to keep the compression at about 8.5:1 during the build. This is just a dream right now, but IT IS going to happen... just haven't actually decided anything yet.

This project is to be a driven road car, not a track or show car. We would like to see massive power under 5000rpm. In other words, we want it to run & idle like a street car; we don't want to go completely over the top with a ridiculous cam (even though the turbos will prove ridiculous when it happens).

Here's the question:
If anyone has built a low-compression 383 before, give me some advice - numbers, parts, vendors, intelligence, opinions.

Thanks in advance... and pictures will come soon.

NonGoggleGuy

This will also be our first engine build by ourselves, so we could use a little heads-up, and tricks of the trade.

Thanks again!!

NonGoggleGuy

Nobody's built a 383 before?

I'm not looking for answers; just ideas, options, and opinions.

Sandmann120

iTrader: (1)

Question- Why a 383? Why not just run a 408?

NonGoggleGuy

Because I can get my hands on an LS1 block pretty easily right now. Plus because of clearance issues in "the trunk." Also, I'm planning on an F40 or Acura NSX 6-speed manual tranny, and I'm almost positive that both those bolt up to the LS1/6.

What block are you suggesting? An LS3?

multmigs

iTrader: (2)

uh a 408 is a $600 6.0 truck block with stroker kit...Same outer block dimension as a LS1 but made from iron and supposedly they are somewhat stronger because of that.

NonGoggleGuy

So they're twice as heavy as well? The Fiero subframe is out of a Chevy Citation, which is not really meant to withstand that much weight. I want to stick with aluminum.

Are the mounts the same with that block? Like I stated, I can get my hands on an LS1, and the motor mounts are also "standard" within this build.

wht01ws6ta

iTrader: (45)

Iron block is about 70 lbs heavier.

NonGoggleGuy

Thanks for the input guys. I still want to stay with the LS1 block, though. I can get it cheap, and I'd like to build one. I have the LS1 in my T/A, and I'd like to know it more betterlier.

NonGoggleGuy

Out of curiosity, I just posted on the Fiero forum about the LQ4. Would there be any benefit (besides durabilty) in the truck engine versus the LS2?

multmigs

iTrader: (2)

probably cheaper at the machine shop due to the block being iron instead of alum like the LS1 which uses press in cylinder liners, other than that, everything part wise would interchange, I do understand your weight issue on the fiero subframe though, I'd say why not just rebuild the LS1 to a 355 with some lower comp pistons that way you can reuse the crank etc, and then do your turbo project.

NonGoggleGuy

I guess the extra weight isn't a HUGE issue. It obviously will provide more traction, but from what I understand, makes it a little too ***-heavy after all is said and done. As far as increasing displacement, I'd rather do a stroke tan a bore. Bores (depending on size) compromise the heat dissipation. Plus, I want torque more than HP. Low-end power is kinda what we're looking for, and we'll select our H/C to maximize that when the time comes. The turbo (if it happens) will be the mid-high RPM range booster.

Since I plan on rebuilding this from square 1, I figure "why not put in a stroker kit?" It's non-intrusive to the block & sleeves.

V8Rumble

iTrader: (9)

Here are my thoughts on which block to use (FWIW):

If you're planning on moderate boost (say 8-10 lbs or less), then either one is fine - but if you're wanting to go crazy with the boost, you'll be happier with an iron block. (Yes, I know that aluminum blocks have been boosted beyond 10 lbs, but that's just my thoughts on the subject...)


And you might also post in the Gen-III Internal Engine forum for suggestions on how to build the engine - it's more directly on-topic there...

Good luck with the build, it sounds like it's gonna be absolutely BRUTAL...

squalor

iTrader: (3)

If I were to try building a V8 Fiero without using the Archie kit/iron sbc, I would try to use a Northstar or a LS4 from a Impala SS. Something that came transverse from the factory.

Pocket

iTrader: (22)

The hard part on the LS4 is the starter and where to put it

http://www.fiero.nl/forum/Forum1/HTML/062546-4.html
http://www.fiero.nl/forum/Forum1/HTML/062546.html

What trans are you planning?
The factory 4 & 5 speeds are pretty weak, you can go G6 6 speed but thats a whole new can of worms to properly swap
Factory autos arent strong either, Northstar 4T80E's will hold all the power but are physically large and heavy

NemeSS

iTrader: (127)

imo your not going about it right the way, what, dont think the turbo or turbos with ic and plumbing are not gonna add any weight?
and not only that the radiation of the turbo and hot parts themselves, in that tight poorly ventilated compartment.

if your looking for alum engine, look for l92 out of denali or escalade, or a ls3 which are 375ci motors. with cam and tune these engines are around 600bhp and matching tq. no need for stroker or tt.
even a lq4 with stock heads, and a gt11 type cam will make all the tq and hp that lil car will ever need. easy 500+bhp and tq

Isolde

iTrader: (4)

I've been active in the OP's thread on www.fiero.nl, but It seems I didn't make it clear that the NSX trans is not a simple thing. It's just a stronger thing.
The Fiero with LS4 and 4T65E-HD comes in around 3100 pounds plus driver. Fiero-able transaxles and axle shafts are not up to a stroked or boosted LS.

NonGoggleGuy

Sure, the turbos weigh something. But the weight would be more distributed. We'd probably do an STS FM. And you make a good point with the already traverse engine. I still need to decide.

NonGoggleGuy

Okay, can anyone tell me if the dimensions & mounting locations are the same for the following 5.3L?

LM7 - longitudinal, iron
LM4 - longitudinal, aluminum
LS4 - transverse, aluminum

I'm assuming the LS4 is different.

Thanks.