You can elongate the hole on an older intake slightly and the bolts will work fine in the center. Put a couple of flat washers under the bolt head. Really not a bad swap at all. Get either an older HEI distributor or a points style distributor, elongate the center holes in the intake, make sure the carb is good. There was one engine I installed that had the block cut for the fuel pump, and the hole drilled for the pump push rod, but the cam didn't have the lobe on it for the fuel pump. Had to use an electric pump with it.