Howdy, my gta has a 383 with a forged rotating assembly and a holley 750dp. There are many more details, but the engine makes about 435 to the wheels. Well thats a low estimate, its most likely more. Anyway, I didnt build the engine so I dont feel like its.. mine.. lol

A guy is wanting to buy just the block and rotating assembly. I'd be keeping the heads and up and the headers also. Ill only be getting $1200 for it though. The pistons alone cost $600+

Anyway, if i sell the engine ive been contemplating swapping to an Fbody lt1 w/ aluminum heads. My headers should mount right up. Ill be down some serious horsepower, but this is my daily driver. Its freezing up here and i want fuel injection. The car has an lt1 t56 already w/ an ls1 rear end 3.42 torsen. I know what the lt1's make in stock form, but since I would already have a good exhaust system (hooker long tubes w/ 3" all the way back), how much would I make? I might would do a cam swap before I drop it in but thats about it. The heads im keeping have 1.6 roller rockers, could I swap those also?

Sorry for q's, thanks!!

 

is your current motor a one piece rear main seal motor?

 

yep original engine for my car, 87

 

i think a healthy LT1 with headers is around 300ish to the wheels. Seen 4th gen LT1 run mid 13's

 

So after a cam swap w/ 1.6 rockers, the headers and 3" exhaust, cold air intake fabbed into my 4" cowl I could probably run a low to mid 12's? My car is alot lighter than a 4th gen. Most of the interior is gone not to mention the 3rd gens already weigh less from the factory. Does everyone think I would be satisfied with an lt1?

 

not sure how much more an LT1 weighs over a v6 bone stock, but 4th gen fbody weighs in the same category as a third gen, coming in around 3300-3500. A fully loaded SS is around 3500, power everything yatta yatta. I believe the GTA's are the fattest of them all.

My friend had a late 80's Z28, gutted the interior, fiberglass hood, notchback hatch, aftermarket rims, some other weight reductions, weighed in around 2850.

Are you going to be using the stock heads on the LT1 or aftermarket? Stock heads i believe can only handle upto .500 lift before you have to do mods to them. All you said was aluminum heads.

I doubt your going to see anywhere near 435whp with a cam, 1.6 rockers, full exhaust from a LT1, especially from stock heads. On a good note though am pretty sure you would see an increase in fuel Mileage, and driveability.

If you do go with this swap i would suggest deleting the optispark, Good ol GM design at its best

 

I would suggest also looking at LS1tech.com, great info on LT1's

 

definitley ditch the optispark there junk.

 

do a 383 LT1, get a cheap LT1, have it machined for the stroker kit in your current engne, and wala, lots of power, cheap.

 

Headers typically add around 10% over manifolds. They help other mods work better as well.

I'd say you will give up a good bit of power, but street driving in the cold - you'll be much happier.

 

after owning both carbed and fuel injected vehicles, I'll never go back to a carb, FI cold starts rule.

 

Get an LS1 or 6.0 with a decent cam and you'll be happier with the powerband and street manners.

LT1's are plagued with the Opti-spark, by the time you figure out the opti or replace it you've spent $$ that could have funded the LS1 swap.

 

The problems that optisparks have had being blown out of proportion and oversimplified. Maybe it's a pet peeve of mine, but I can't stand when someone says "it's garbage" and leaves it at that. There are plenty of cars out there running just fine with an optispark... it isn't nearly as bad in reality as its repulation would indicate.

The problems experienced fall into 3 basic categories.
1- the early versions were non-vented, which lead to moisture getting trapped inside and decreasing its life. The '95 up and currently available replacement parts are vented and don't have this problem.
2- They are located underneath the water pump. If someone removes the water pump and doesn't know or care enough to protect the optispark, coolant can find its way inside.
3- They die of natural causes with high milage and people who are used to older style distributors don't diagnose the failure quickly. At the end of their frustrating hunt, they say "damn that POS Optispark!"

They really aren't bad, they're just misunderstood :-)


Back to the main topic though, It sounds like in the end, you'll lose HP, spend lots of your time to swap the engine and do all the electric work ( I know, I've done it!), and probably end up losing money when all the parts for the swap are added up. That's a lot of cons stacked up against the one pro of having easier starts with fuel injection.

 

local guy here made about 285rwhp with adding a full exhaust on a 95 lt1/4l60e. he prolly had cold-air too, but i can't verify that.

I'd say another 20 at most with a cam and tune if you go that route.

 

I think a healthy LT1 with cam/tune is more capable then just 20hp.

Take the money your gonna end up with the swap, All the time to do the swap, and build a heated garage and keep the 383 :P

 

I dynoed my car today on a dynojet

365HP and 427TQ to the wheels. Do would it be good to get a lt1?

 

Id keep the SBC

 

whats heads you running? 435 and 365 to the wheels is night and day

 

I still say both, like I said, get a LT1 in need of a rebuild, use the rotating assembly out of your 383, and wala like magic you make big power with a modern powerplant.

 

Id keep the SBC and use a single plane EFI manifold, a custom LSx SBC harness on a SD tune. Same/better power with alot better manners

 

what kind of heads do you have on your current 383?

 

i have pbm heads. i dont know much about them. 220cc runners and 58cc combustion chambers. normal valves

 

never heard of PBM, are they aluminum or iron?

 

There's nothing wrong with the optispark. They last better than most typical Gen 1 distributor parts do, and its a far more accurate ignition system. People always complain when they replace a GM one with some cheapo knock off and wonder why it failed. Its the junk cheapo parts store parts. Same thing happens with normal dissy parts too. Use good parts, they will work and last just fine. Mine does.