I may be getting a set of L36 heads, and I'd like to know how much they can be milled before piston/valve contact is an issue. Can it be done or do I need to pick up some pistons that are either dished or have valve reliefs?

For safety I don't think that I would go past .010 with stock pistons. Probably should have a machine shop look into that one for you.

You want to make them flat or up your compression? You could use thinner head gaskets if your heads are already true, save a few bucks? 10 thou is not unheard of btw.

I figured that wasn't unheard of......Just I haven't heard it done on L36'*. Nor am I too familiar with their clearances.

I'd imagine that he'* milling the heads to up the compression. But chances are the engine that he'* getting the heads off of has been overheated pretty good....so he may need some milling just to flatten them out.

You're right on both counts, Nate. The heads may be warped, but even if they're not I'd like to get 'em milled for more compression. Is this a question better suited for Todd or Scott?

I'd figure that Todd would know for sure. I'd say 20 thou before you need different pistons.

Check this out:
http://www.zzperformance.com/latest_news1.php?id=48
I'm guessing you can probably mill the heads 40 over with stock thickness head gaskets but i know you can mill 30 over with .052" headgaskets.(someone on clubgp is running it now) You will need 7.0" pushrods to keep correct valvetrain geometry.

Just be careful if you start messing with rockers and cams. You could run into the valve smacking the piston then


-justin

Which is where the 7.0" push rods come in.

for the stock valvetrain.

Not aftermarket.


-justin