hey guys I have a used lq4 which as been bored from a 4.000 to a 4.005 and I want to run boost on it but can't use stock pistons..any good 5-600 $ pistons i should try out ?? thanks

 

Summit Pro LS Pistons

 

OP,

You may have already found your pistons but we figured we would jump in just in case. Our 2618 alloy forged Pro LS pistons were designed for boost. This will be helpful for future members as well. With an LQ4 you could have either a Gen 3 (.945") press-fit pin rod or a Gen 4 (.943") floating pin rod. That's dependent on the year of the engine. 99-04 you would have the .945" press-fit and for 05-07, you would have the .943" floating pins. This doesn't take into account you could have an 04 or older LQ4 that someone has already put Gen 4 rods in.

Being a boosted application and assuming you're keeping the factory 71cc heads we would go with our 12cc dished pistons. With the 12cc 4.005" pistons you'll be around 9:1 with 3.622" stroke, and factory .051" head gaskets. Our pistons are designed to sit .005" in the hole with a factory 9.240" deck height.

Pistons
- For use with 6.098" Gen 3 .(945") pin press-fit rods: SUM-326945400512
- For use with 6.098" Gen 4 (.943") floating pin rods: SUM-326943400512

Recommended file-fit piston rings for either 4.005" piston
- SUM-136SN9045010