flipmike22

So it seems like I got some knock. I think it's time to stroke my ls. I'm currently running stock ls6 block with 2.5 243 heads, ls7 lifters, tourqer v2 cam and a 102mm intake(ported) and tb. New billet lightweight steel flywheel and stage 3 monster clutch. 2.5" true duals out, 43lbs injectors.

Any opinions on the 4.1 x 3.9 stroke and bore?
Any kits suggested?
Dyno numbers?
Cost and all?
Etc.


Any help with how about I should go with this would be great. Don't know much about v8's since I'm a proud owner of a ls powered nissan 240.

batboy

iTrader: (6)

I would not go more than a 4" stroke on a LS6 block. The 4.1 and 4.125 cranks pull the piston down too far out of the cylinder bore which causes excessive wear. Due to wrist pin placement which moves the ring pack up, the pistons for this stroke have a narrow of crown, which reduces strength. Check out the 383 forged stroker rotating assemblies at Texas Speed.

flipmike22

Ok thanks a lot. I was considering the 4.1 because I've read some reviews on a f body and was mentioned it was safe. Now you're saying its not. I'd rather have that peace of mind and keep that little amount of certainty haha. What numbers do you think I should expect with the bolt ons I have? If I go with 4.0 with a 3.9? And any suggestions on the pistons, as far as manufacturer? Also what's your opinion on a 4.0 x 4.0 is the bore too much for a stock bottom end?

batboy

iTrader: (6)

Can't bore out a LS1 to 4" unless you resleeve it. It's common to hone the bores out to 3.905". As for pistons, Wiseco, Mahle, and Diamond are all good.

As for stroke above 4", I would not necessarily say it's unsafe, just doesn't have the same longevity. The 4.1 and 4.125 strokes tend to start burning oil faster.

flipmike22

Ok any opinions on the pushrods to use?

JakeFusion

iTrader: (7)

Manton 11/32nds.

cdubbzz

iTrader: (11)

There's not that many of us out there but I ran a 3.915 bore with Eagle forged 4.100 crank for 7 years/20k miles without ever touching a thing internally. I recently wiped out a cam bearing and had her tore down. The pistons/block show some wear but rotating assembly still looks brand new. The engine did consume some oil since day 1.

I feel like I'm beating a dead horse with this but my combo made 500rwhp/500rwtq, ran high 10's@129mph and looooow 10's@138mph on a 120shot.

Crank is for sale if you care

dr_whigham

iTrader: (49)

Wasn't that the the 395/396 kit that Eagle used to sell? It's actually a kit I've been really interested in myself. Something about saying "It's a 396" just blows my skirt up... Makes me miss my old 65 Chevelle.

Pardon me while I go dig through some of your old posts....

batboy

iTrader: (6)

With a stroker LS1 you can get 396 with a 3.91" bore and 4.125" stroke. But, you have to clearance the block a lot and still have the issue about the pistons being pulled to far out of the bottom of the bore like I mentioned in an earlier post. For every post I see that saw they used more than a 4" stroke with no problems, I can find another post where there was excesive wear and oil consumption. But hey, it's your motor and your money, do whatever you want.

garygnu

what would be the rod to stroke ratio ?with a 4.125 crank there would be some extra pressure on the thrust side of the bore ?

batboy

iTrader: (6)

Yes, there would be more side thrust plus the piston crown is thinner because the wrist pin location pushes the ring pack up. These long strokes are definitely not recommended for boost or nitrous.

dr_whigham

iTrader: (49)

It's actually a 393. The Eagle kit uses an LS1 with a 3.905 bore, but not a 4.125 crank though, it was a 4.1

I believe it's the Lunati that uses a 3.903 bore with a 4.125 crank

https://ls1tech.com/forums/dynamomet...acing-cam.html

https://ls1tech.com/forums/dynamomet...yrs-later.html

Some #'s ideas in this thread.

https://ls1tech.com/forums/generatio...5-stroker.html

Since I have a 1168 block, this is probably the route I'm going to go. I can't justify picking up another block when I can put that money toward Mamofying waht I already have.

s346k

iTrader: (4)

i have a friend using a eagle 393 in a na 7800 rpm application. I think he made 540 whp in a 243 headed link bar setup with a hyd cam. went high 9s 134-136 in a m6 fd rx7

flipmike22

I'm really stuck on deciding my set up. I'm just sitting on cash and don't really know what set up to get!!!!

I'm really digging the 396 but I wouldn't want to sacrifice too much just for a few more ci's.
Now this car is not my daily but I do plan on doing some hard driving about 2-3 days a week. And I want it as reliable as possible.

Anyone have an estimate on gains with my set up to a few kits. I make 448hp and 383tq this is to the wheels.

therabidweasel

iTrader: (5)

Ive been torn with this question as well, my car is now built to hell and I want to go ls2/3...but my mamofied 215s just seem wrong for those blocks and are way too sexy so i think id like to stroke it...and my motto is NOTHING in moderation...please document what you do, been eyeballing that lunati crank. What few results there are on here are pretty damn impressive.

Lme was having a sale on ls2 stuff though...

flipmike22

Now I've been searching does anyone sell a full rotating assembly kit for a 396? Or do I piece it together myself?(package deal seems cheaper)

batboy

iTrader: (6)

I still say the power gains are minimal between a 383 and a 395 motor on top of the oil consumption and piston skirt wear issues already discussed. You also have to do a lot of clearancing. That said, it's your hard earned money, if you want to blow it. Thunder Racing sells 395 rotating assemblies.

flipmike22

Also the bore is bigger which I'm trying not to go past 3.903. Just because it puts my mind at ease.

Would the 393's have clearance issues also?

batboy

iTrader: (6)

It's the long stroke that causes the problems, not the bore. Nothing wrong with honing a LS1/LS6 to 3.905"

flipmike22

Ya but I was told a 4+bore would not be suitable for the cylinder walls. What clearance would be needed with the 393?