Just a quick mention in why and how good a purchase of a OD trans is a good thing no matter what kind of engine you build is the gear spread and final drive ratio you get when you multiply the rear end gear by the OD ratio. Once you find the cruise rpm at what ever speed you want it to be at, you can work the engine cam question in reverse with the above numbers. In an example, instead of being stuck as you would say with 4.30’s as a final drive ratio, you could re-cam the engine for the final drive ratio and so very well. With or without the big cam.
The purchase of a Chrysler OD trans w/converter will knit require a shortening of the driveshaft and ether purchasing a trans Mount or fabbing one up yourself.
The cost of wires and a OD on/off switch is peanuts.