I bought a 5.3 lm7 and I need to change out the pistons. Can I change to lm4 pistons? What change will they have for compression? Just looking for a little info from someone who knows better then me.

Thanks

 

Any 4.8/5.3L pistons will fit

LM4 was a different class of the same bore block family

 

Why do you need to change pistons? That said go 10 over to clean up the bores and run flat tops for compression, unless you plan to turbocharge then you want dishes. And to be clear new pistons not used. Never use used pistons in any motor they didn't come out of.

 

I will say that used pistons from a engine into another that was bored over is ok, 5.3 bored to LS1 with used pistons or 6.0 bored to ls3/l92 with used 6.2 pistons is ok. Never had a problem with that on a budget.