Originally Posted by ernkazern
I imagine you want to know how much dish your pistons have so you'll know what your compression ratio will be with the new heads? If you know what your compression ratio is now and the cc of your present combustion chambers you can make a good educated guess as to where you'll end up with the new heads.
That's correct. As far as I have read the stock heads(76cc)/stock pistons make a compression of appr. 8.5:1. This would appr. mean a 20cc dish.
If this number was correct I wouldn't see a problem with 64cc iron heads since this would give me a compression of appr. 9.5:1.
OTOH I've read somewhere else that the stock engine has appr. 9.0:1 compression - which would produce >10:1 with 64cc. Maybe a bit too much for iron heads.