Reply to "Compression too high?"

The domes on the pop up pistons are usually hollow. If they were solid they would add a lot of weight to the piston.

The TRW pop-up simply can't cut this much off of the dome without holing through. I realize these are Ross pistons but specs are usually very similar.

The piston to wall clearance on the TRW is big. It is .0055".

The picture you posted looks like it is h-u-g-e!

.030" top, .005 bottom. I know the clearance is measured with a ribbon so the picture may be deceiving but it surely looks strange from my view from here in the cheap seats?

I think the number for piston to valve on the intake is .100" and .080" on the exhaust? I might have that reversed, I have to look that up to be sure. I haven't built a C in a while.

What are the lift specs on that cam? I want to say (offhand) that you are good to about .630" lift without having to cut the pockets?

You could use the lifter bushings installed too while it is apart.

You WILL pick up some free horsepower if you index those spark plugs.