92 p/c's for my 90 c2
 

i have found a set of low mileage 1992 p/c's that i'm thinking about for my 90 c2 which have the sealing ring groove. if i were to use these on my rebuild, do i have to machine my heads to accept the sealing rings?
any pros / cons to doing this?
otherwise i will have to machine the cylinders and heads i already have.

Yessir, you will need to machine your heads for the later sealing rings.

Properly done, its a very robust repair.