Originally Posted by
MOBILEMERCMAN
You are going to want to take drives off and send them to some competent dealer. They require special tools and not everybody can work on them. Even if you don't send them out you'll want to take them off to change fluid grease and inspect cross bearings. Plus it is very difficult to install engines with drives on.
Rear mount is nice to have but very difficult to fabricate mounts to stringers and align properly with assembled engines. That is typically done with a dummy block bolted to trannie assembly. For the sake of not overburdening yourself just leave it for now. You can always attend to it in the future.
Steering is typically on stb engine. The inside transom plate will dictate that.
Flywheels are not interchangeable. you must use flywheel that came with the engines. Ring gears can be moved in many cases. Flex plates are inter changeable. The bigger the springs the better. The 540 likely had a heavier duty flexplate. Hardin sells HD flex plates at a reasonable price.
Back to drives. I believe it is very important to know they are good. Few internal parts are available. Fewer used assemblies are available. If your drives are beyond repair it changes the entire job.
Hopefully the fluid is clean and no moisture is present. They must hold lube. if the lube is creamy drain and refill and send out. Never drain lube and leave empty. ESPECIALLY is water is present.
Best of luck. I'll check in when I can.