'69 Barracuda In Georgia

Welcome. Sounds like you have some good plans for the Barracuda. All of the changes you want to make are pretty easy. Changing from a 318 to a 340 is just a matter of getting the right motor mounts as long as you already have a V8 K-frame. Upgrading to 4.5" bolt pattern can be done up by getting the disk brakes off of a 73 and up A-body. Changing to an 8 3/4 rear is a bolt in process and axles can be bought new with large bolt pattern. Ditching the power steering is also easy, especially if the engine is going to come out. Get a manual steering box from most any old mopar and an adapter for your steering column. All easy stuff but you will be parting with some $$.