The motor mounts are the same, the bellhousing is the same, the flywheel is the same, etc. The shock towers will be tight as the are on a 69/70 as well. It can be a simple swap if you keep in mind the following items: Make sure you get a motor with all the accessory drives (pulleys, PS bracket/pump, alternator bracket, etc) and watch the water pump outlet side. Some small blocks have a left exit, some a right side--this affects your radiator bottom inlet... Radiators can be modified or a new one bought to fix this so easy enough to take care of. I had to modify some wiring (lengthen) to install a Cleveland where a Windsor once sat. The last thing I had to do related to carb height as I have a shaker hood--the Cleveland has a taller carb base height. I eliminated my under carb spacer and had to modify my shaker (don't worry or flame me--my shaker is bogus underneath the visible scoop and I did not screw up any original bits.)