blackz97

Given stock heads, stock valve sizes, stock head gasket, and stock pistons _generally_ how big can you get with a cam in these LS7s before you start running into piston to valve clearance issues?

Steve

5280Racer

Steve, I ran a Lingenfelter GT21 cam with .006 milled off the bottom of my LS7 heads and hair shorter pushrod. no issues.

Mark2009

PTV clearance on the stock setup is about 1/4 inch. Seriously.

But there are issues other than lift, such as when that lift happens (e.g., duration and timing). You'll need to talk to a cam expert. Especially about high lift, since some of them say it is not needed/'cost' effective on this engine... especially if you don't port the heads.

blackz97

I see that the stock pistons have reliefs which is going to help a lot. I just wanted to run it by some other Z owners first.


Im hoping to get away with a mid 240s duration on the exhaust side without fly cutting. On LS1,2,3 engines that do not have reliefs, that mid 240s number is starting to get close (esp if your milling and running a tighter gasket). Given what you guys are telling me mid 240s should not be an issue at all.

Thanks for the feedback.