[Jack21]

There are two approaches I've seen to use roller cams in non roller blocks in SBF's; one from Crane Cams, and one from Competion Cams (CompCams).

Crane uses a standard base circle cam and a custom short lifter supported with a link bar between pairs of lifters. Comp uses a "retrofit" small base circle cam, and stock Ford lifters, spider, and forks between pairs.

Both methods work, but are not interchangable. Roller blocks have taller lifter bores to accomodate taller roller lifters. And shorter pushrods are used.

Sooo, if you're using say, an FMS (which is a standard base circle) cam in a '69 block, you need to be using the correct lifters for a non-roller block. (Or swap the cam for a small base circle for retrofit use). And, you may need a new set of pushrods with correct rocker arm geometry dialed in.