just keep it simple, use the much larger, 2mm , 22R valves in the 20R head,
i have one at the machine shop now getting 22R valve seats put in it, $8 per hole
the LCEngineering stage II is about as high lift as i would go, duration does ALOT for the little motors, i took a 1 1/4
maybe 1 1/2 forstner bit to open the exhaust ports to match the header
after i finish i would love to hookup with BIGMIKE and his 3rz for a nice little road race
