I've been told that a left side exhaust manifold from a 1955 or 56 smallblock will actually clear the steering box without mods;that might simplify at least one part of the project. For a front mount,there's a few options;aftermarket mounts,the 55-59 truck V-8 front mounts,the 60-?? truck V-8 "saddle" mount,or weld in a handmade crossmember and use side mounts.My choice would be the 60-?? saddle mount;it only has one pad to find a place to attach,right in the middle and just ahead ofthe face of the block. Throttle linkage can be a nightmare,or you can swap in a cable set up from a 70's up Chevy pick up. 3 screws to attach the pedal,a square hole in the firewall to plug the cable housing into,and a bracket on the intake manifold for the other end of the cable housing.
You'll need a truck V-8 starter too. Parts stores have 'em in stock. You might have to build a clutch rod too-no big deal.
None of this is too tough-just take one thing at a time,and work on it until you're satisfied with its operation and appearance. Before ya know it,it's done.
In all honesty though,another six would be easier to fit,and unless outright power is really important to you,a six will be a lot more satisfying.
Speed