Just bought my first mopar. Looking for help!

Nice AC and all. Great start for $300. Small block is the easiest since it was a 318 car. 273, 318, 340, 360, 5.2 Magnum, 5.9 Magnum, or a stroker depending how much you want to put into it. Then you can go big block B engines 361, 383, 400. Next is a RB 413, 426, 440. Then there are Hemis, 5.7, 6.4, 426? Pick your engine first since that will help decide the rest.
Okay since it was a small block car, will I need to change anything out via subframe.. If I wanted to go 440??? I'm used to chevy where almost everything is interchangeable lol