I appreciate all the info folks. Never had the opportunity to mix and match before, usually I went for whatever would fix my vehicles pronto. I had 4 kids, myself, and my wife in separate vehicles that had to run. Now I have more vehicles than people and some time on my hands finally to do some car work on what I want to, not what I have to.
So I'll probably go get me another 318 and an 8.25 and do the Dart up right from the start. It has the 904, so I won't have to get that. Would I need to change the converter?
I'll just tweak the truck and give it some paint. Maybe I'll even let my son have it back. HA!