Its my understanding that if you take a lq based block and make a 402/8 that the piston skirt comes out of the sleeve at the bottom of the stroke, thus severely affecting the longevity of the engine. Is this true? If so how much can it affect the lifespan? Keeping the stock stroke and doing a 370 would eliminate this, correct? I do not want to spend the money if it wont last. Were talking abt a summer/good weather/weekend/occasional track use car btw..Thanks

 

One can remedy this issue by getting correct length pistons. In general 4.0 stroke or less is pretty reliable. There is however no substitute for displacement

 

Would you happen to know the length of piston that is correct?? Is that an issue that a vendor can help you make the right choice with when ordering (I hope!)?

 

Yes, I've used Ross pistons

 

If your vendor can not get you the correct pistons with the correct rod length, you need to find another vendor!

I too use Ross pistons. Nothing short of the best!

 

the LS7 in stock form uses a 4" stroke. so if GM would do it, then i dont see a reason why you shouldn't do it!

 

Wiseco also makes some excellent pistons for this application and has the largest selection of shelf pistons I have seen.

 

Well is the cylinder sleeve the same length in the LS7 vs the other engines? Cuz that may be why a 4" stroke works fine.

It's not that 4" or more is magically not reliable, it's the fact that it might be too much of a stroke on the stock sleeves of LS2s 3s 6s 1s etc.

 

You have the same issue with the LSX block. What everyone is telling you is with the corret rod length and piston design, there is no issue. If your builder is cared of the 4 inch stroke in the LS platform, leave him. He does not know the LS platform. There are thousand apond thousands of 4 inch LS engines running around making killer hp. I am one of them. They are reliable, very reliable if put tegether right. the 4 inch stroke is probably the most popular stroke when upgrading.

 

LS7s do have a longer sleeve. It is an issue but if it's properly setup (pistons designed for this) it seems to be ok. The gm LSX block has the same issue. I always wondered why they didn't make a slightly longer sleeve in the LSX.

 

I have diamond pistons with a 402ci. THE MORE CI'S THE BETTER.