Lt5 383?
 

Can the 1990-1995 LT5 motor be stroked to 383?

If so what are the benefits? Are there any special problems with doing this?

Thanks

Yes the LT5 can be stroked to 383. One of our Wazoo group, Secondchance did it and another has gone to 427. Sure they will chime in to give the pros and doubt if any cons.
Charlie

The latest configuration is a 391 from Dr. Greekenstein in Des Plaines, IL. 600chp w 132mph trap.

600 crank hp does not require the big bore, closed deck short block. It is done with a 6.0L 368 cid, with the right cams and induction. I've done two in the last 24 months. Not many (any?) actually test these things on an engine dyno. Don't accept the rule-of-thumb "conversion" from rolling road dyno to engine horsepower.

BTW Todd, do u have any expectation for power increase JUST from the use of COP? Or is it just to accomodate the new ECM?

In the past there were some 385 cranks done. I have one and went with larger pistons for a 396.

396. What a lovely number.

best trap I ever got was at bg 131 with street tires

pete is making some good steam

380-390 seems to be a good displacement

head flow limits getting good results out of the big strokers

I hope to see around 540 at the tire next go if I'm lucky with a bit more porting than JL put into the LSV

it will be interesting to see.

In the end, the critical path on our LT5 is the heads simply there’s no other way to increase flow w anything aftermarket. The ZR-1 community, ie Todd, Pete, Mark, Corey etc., have been marvelous at eeking power out on a DIY basis. At ~ 550chp, these cars are a blast to drive around. Even after 10 years of ownership, I still love getting in and running around. And that’s saying something for me.

LSV baby guesses
 

I'm amazed at the numbers the good heads will give. I have a great experiment coming and would like to see what you all think

going with the MLS hg which will raise compression just a bit, heads were evened out and opened up from 33 to 34 to max porting all around 36

staying with same 3.785 sonny bryant crank, pankl ti rods, and JE pistons

stg 2 cams 234 at 424 430 lift, something like that

car was pretty repeatable around 508-516 at the tire, torq around 430 (a bit low to me)

best mph 131 at BG (don't run the car too much now) JL has a 619 engine dyno run which showed the engine was doing well (a bit optimistic)


soooo....... I'm hoping to go to 545 at the tire which might be a bit optimistic but that's the target I'm shooting for and where I'm calling it. trq at 434


Looking for some recommendations to "better that number" I have the engine apart and need some advice

what ring package should I run for the J&E pistons running close to 13-`1 compression (I'm headed for E85 if needed

I think these pistons are 1/16 upper and 3/16 lower

should I get this piston skirts coated? Piston tops?

any magic pixie dust I should sprinkle on the dyno? ( grin )

I'm leaning towards a dual disk alum flywheel setup from Jerry's to try and hook all this

for this coming year I have some ccw 16 drag radials and front skinnies so we can bolt em on and see how they do

ditch the front sway bar, woo hoo!!! next thing with the dual disk and more power, snapped spindles (maybe the old fidanza isn't such a bad idea to "slip a bit")

thanks for any sage advice. The LSV needs some LOVE

So if I were to take a C4 ZR1 to my local speed shop, would I expect to pay more to stroke it out to 383 then say a 1996 LT4?

Im sorry I am not near the level of you guys with this.

Thanks

great mph !

Wooooosh LOL

Tyler

Short answer: Yes, significantly. The LT5 is a limited production engine, a drop in the bucket compared to LT1~LT4, so the aftermarket is not nearly as prolific. And then there's this; it's a 4 cam, 32 valve engine with 16 fuel injectors...... 4 times as many cams, 2 times the number of valves & injectors.

Perfect answer!!

396, now that’s an engine combo I’d like for my Z. That and I’m a sucker for throwbacks to old big block cube numbers. Although I’m pretty sure the cost of that build is a five digit figure that starts with a “2”. It’s interesting the 385/391 combos make similar power to a 415. The power gap is smaller between these combos than it is in pushrod world.

Late to the conversation, but I love my 391 from Pete. This thing is an absolute blast and surprises a LOT of people. Haven't had it dynoed yet (should be 600+HP), but it did 176MPH in the standing mile, which is at the bottom end of what C6 ZR1s do in the standing mile (177-184 depending on track and weather). And yes, it is amazing that Pete is now getting power from a 391 that's equal/better than 415s of only a short time ago for significantly less money (although it's still expensive).

OK, so to save on some cost, will the C4 LT5 work with a Vortech Supercharger system designed for the C4 LT1? Would this work with the Z's engine and would there be any extra costs involved as compared to the LT1 installation?

Evan,

Did u get a number for what the car was doing at the 1/2 marker?


My first question would be “what does an LT1 get for HP w the supercharger?”

Boosted LT5
 

Supercharging the has been discussed frequently over the years, but only resulting in 1 successful attempt. Randy Wood used his car as a prototype, but never offered a kit.
Turbocharging the LT5 has been done in a variety of styles, front, rear, dual & single. Dual front is the preferred manner, but cost is high. To realize enough gain in power, really requires rebuilding the engine for low compression, 8-8.5:1 so boost in the 15psig range can be feasible. With stock compression at 11:1, 5 psig is all that can be run safely. That’s not enough power gain to justify the cost to turbocharge.

About the LT1 Vortech Supercharger system: There are major differences between the LT1 & the LT5. I would expect to encounter significant obstacles trying to adapt it to the LT5 engine. Anything is possible but I think adapting to the LT5 would incure significant "extra costs." If it were simple, it would have already been done several time over.