I did a quick look at my manual and it doesn't give detailed instructions for engine removal and installation I stand corrected and Poorboy and zrxkawboy are right.

".....Most of the factory service manuals from the 40s & 50s make the assumption the mechanic is capable of pulling a motor out of the car without instructions....."

Another part of the explanation is that back when these cars were new when it came time to freshen the engine it was most often done with an "in car" overhaul. Basically the engine striped and the block and crankshaft were left in place. Valves were often just lapped and if they needed ground in the case of the flatheads, the valve grinder was a simple (and portable) hand grinder. There was even an "in car" crankshaft grinder if the crank needed redone.

The Plymouth bumper is not quite as complicated as the Dodge bumper (which for all intents and purposes are really 3 bumpers), but on the Plymouth there are brackets and bumper bolts on the very ends that are a real pain).

As far as the motor and transmission mounts the 6 cyl ones are a bit simpler than the V8 can mounts and can be left bolted to the engine and transmission respectively. The emergency brake cable and shift cable (if it's an automatic) will also need to be disconnected (that is covered in the shop manual). I would also recommend removing the engine fan for a couple more inches of clearance.

Personally I like the method of removing the engine that Gene describes which is as the engine is lifted moving the car back out under the engine rather than trying to move the cherry picker back (which usually sets the engine swinging). The engine leveler allows the steep angle needed to initially clear the radiator support and as the engine comes out it can be brought level again once the transmission clears the tunnel.

Finally one thing you may or may not be aware of ……whether you have a stick or an automatic you will find that the flywheel/torque convertor is NOT held on with crankshaft bolts. They both use studs pressed into the flywheel/convertor that pass thru holes in the crankshaft flange and are retained with nuts on the engine side of the crank flange. In the case of the automatic this can be a real PIA to line up and get started when you leave the transmission in the car and are installing just the engine.