so u mean does all the pistons/rods etc from a erst block fit into a frst block,

not sure as never done it, but i would so the pistons will fit as they proberly the same as erst ones, but how can u ensure the pistons will have the same wear as the frst bores?,

is the frst block fcuked u have? and u want to install a s2 engine running efi?

i would use the s2 engine with a mfi - efi adaptor plate, and find away of using the other ways to get round the cps problem u have they are ways (toothed bottom pulley, or camshaft pulley) but ive never done it only seen it , somebody on here must know