From memory.....for what it's worth....
The front mount is a plate that bolts to the block. Replacing that plate requires removal of the timing cover, crank gear, and cam gear (probably easier to remove the cam, but also requires removal of the rocker cover, pushrod cover, rockers, pushrods, lifters, as well as distributor) and the oil pan has to come off as well for two final fasteners.
Or, as an alternate solution, and assuming you're not looking for a 100% factory install and the engine has an existing front blank plate, source a bellhousing for the rear mounts, square the motor up, and matchdrill the existing blank plate from the bottom. Use the largest bit that fits the hole to find center, the drop down to a smaller pilot bit and step the hole up to final size.
Naturally, swap your clutch and starter over.
