With a non-roller block you are supposed to use the smaller based cam and i think special roller lifters because the locations of the oil hole is different from roller to non-roller blocks. If the top of the lifter bores are not machined flat, then it is a non-roller block. With the smaller based cam, the lifters ride a little lower in the block to compensate for the oil hole location difference.
This is unless they now make a lifter where you can use the regular cam. Best bet is to call Crane again.