what if the dome isnt shaped like the top of the piston

 

it should still give you a measurement.

 

right but it might me thinner at the edge or the middle then you would use the smallest thickness

 

I knew I was only going to take off .020" and the head gasket was bigger than that. So, I bolted the head on with no gasket and turned it over super easy and slow to see if it had clearance.

 

Once you had the head off you could put something in there that is soft enough to form to the head but firm enough to hold its shape, then measure it. Something like play dough.

I wouldn’t move the piston with something like that in there. I would get it to TDC with the head off then clamp the flywheel to hold it there then bolt down the head. Would also apply oil to the top of the piston to make sure it doesn’t stick and make a mess in there.

 

I use clay to mock up for head clearance. U want to place it at the edge of the piston parellel to the piston wrist pin. You do this becasuse the piston rocks in the bore toward intake and exhaust port which will give you a incorrect reading. I also place a little oil on top and bottom of the clay to keep it from sticking to the piston and head. Use a dial caliper to measure the thickness. It would be safe at 1mm or .04" of squish

 

.032 is the absolute minimum squish you can safely run on these motors. Any less and you risk piston to head contact at higher RPMs if you have any rod bearing wear at all. I shaved my wife's head .015 and came up with .036. That is with a Moose head gasket measuring the same as an OEM gasket. I have heard that Cometic head gaskets measure a tad bit thinner when compressed.Bubba