My Avatar (62 Uni) had a I6 and 4 speed. When I got her it had a 390/C6 dropped in.
We pulled the engine to replace the front C6 pump seal and freshen everything up.
I towed several 50's cars across the country on an auto transport or a tow dolly
without any problem at all. There should be pic's in my albums that show the mounts and stuff.