Lt5 383?
#2
CF Member



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
Charlie
#3
CF Senior Member



The latest configuration is a 391 from Dr. Greekenstein in Des Plaines, IL. 600chp w 132mph trap.
#4
CF Senior Member



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.
#5
CF Senior Member



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?
#7
CF Senior Member


#8
CF Senior Member



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.
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.
#9
CF Senior Member



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.
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.
#10
CF Senior Member



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.
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
Last edited by Rkreigh; 02-12-2019 at 06:42 AM.
#11

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
Im sorry I am not near the level of you guys with this.
Thanks
#12
CF Senior Member



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
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
#14
CF Senior Member



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.
#16
CF Senior Member


Member Since: May 2004
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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.
Last edited by 1985 Corvette; 02-14-2019 at 06:33 PM.
#17
CF Senior Member



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).
#18

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.
Last edited by vermatrix; 02-15-2019 at 11:39 AM.
#19
CF Senior Member



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).
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?”
#20
CF Senior Member



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.
Last edited by A26B; 02-16-2019 at 08:20 PM. Reason: Added commentary regarding LT1 supercharge kit