How do I measure piston dome

[chainmaker]

Ive been thinking about My winter projects and I was looking at Pirates Billet Head it says>>. This Head works on the GT5 and other motors with the .060 domed piston and only works effectively on the .060 domed pistons. If you use this head on a motor with the .030 piston you will soften your compression, loose power, then wonder why.. These heads do NOT work on the Grubee super rat motor. how do you measure the dome on piston. Can someone translete this maybe some pics? I have a Zoom 66cc slant head and wonder if this would be an improvement.

 

[MotorBicycleRacing]

was looking at Pirates Billet Head it says>>. This Head works on the GT5 and other motors with the .060 domed piston and only works effectively on the .060 domed pistons. If you use this head on a motor with the .030 piston .

Those numbers are incorrect.

Manic Mechanic is the designer of that head and the measurements
are in the photo below off his website.

The correct info is here.
INFO

The MM Gen II head is the improved version.