Richie333

im currently in the process building my motor, block is getting re sleeved since one sleeve cracked and I was just going to do a N/A build but kinda want to add some boost. I'm doing forged pistons and rods also. My question is how exactly do you lower the compression so I can run more boost? What has to be done

Patriot Six

Dished pistons. I've got custom CP pistons with a 15cc dish to give me a 10:1 compression on my LS7. May require new heads, if they've been milled.

Richie333

Heads are milled .30 so the compression is about 11:8 right now. Is there a way to get custom dished pistons and still drop it to around 10:1? I don't really want to get new heads

Patriot Six

You would have to use a compression calculator, but a bigger dish piston (~ -23cc) would be needed. If running e85, I would keep the compression closer to 11. The other issue to consider is how much boost you plan to run and whether the heads will lift or not since there is a thinner deck surface.