Buying the mtc piston 1135 12:5:1 on a 1981 1000j bottom end with Andrew 3x cams what head would best work with my combo and what year? I don't know if I should look for a 1983 84 1100 head or use the 1981 1100 head. Or just use my j head ? Looking for somebody to point me in the right direction
Use the earlier plain hemisphere 1100 or the 'J' head if you want a straight forward assembly.
The later bathtub (twin swirl) head as used on the gpz unitrack and later 1100's has slightly steeper valve angles which may cause valve to piston crown clearance issues and will involve claying the pistons and possible machining of the valve pockets to get the correct clearances.
