5.2 Magnum Build

Im not even sure if I need 400 up, that was just what the article was claiming. I could probably be do with less. The car is a 72 Dart Sport that I'd like a little sportier.
I've been thinking about 340/360 combos where I would have to source a bunch of parts including the the short block. I have a 383 4 speed in a 69 Satellite that is pretty stout. After being into that for years. I thought I would explore the A body world. I'm really just looking for a peppy small block with a 904 or 727 behind it. No drag or street racing just enough to have a little fun and annoy the neighbors.