biggest valve for stock fly cuts

With a decent lift cam 2.02's can have some difficulty fitting with the stock pistons. !.90-1.94 at the most should fit a majority of the time without issues (still not an absolute guarantee though).

I agree 1.94's x 1.54's are about as big as you want to go with......and that with a stock cam. Port that stock lower ( I may do a tech article with pictures soon on that) and throw on that 65mm tb it will make some good power if you dont have any piston to valve clearance problems!. Just get a little modeling clay, or play do (non stick kind) and bolt your heads down on your engine, and roll it over with a rachet/socket and then measure the clearance. shouldnt be to hard.
good luck
Jack