I put a 292 in my 48 3600 2 years ago. I ended up modifying my rear cross member, using d*dge 340 engine mounts to hold the bell housing to the cross member. For the front motor mount, I had a local shop with a CNC torch table cut a wide "u" to bolt to the front of the engine, beside the timing cover, welded angle iron to it, and used a snow plow cutting edge as the motor mount on the front. The fan lines up ok with the radiator, I run a 6 blade fan, and it never overheats. I am running a T-5 behind it. I did not use a transmission cross member.
Side mounts can be done, there are plenty of kits out there, but I have no experience with them. You will need a transmission crossmember, which should not be difficult either.
Good luck
Jon
