Before I make a mistake please help new mopar fan!!

You can also try and find a 400 they make great stroker motors. Look around here and see what others are using for parts. Your stock drive train may not be up to snuff either. Will require a new drive shaft, brakes, maybe rear depending on what you have. And a tranny. If you find a 73+ disc set up snag the whole front end of it. Then use the spool mount K frame and move the mounts. Jim Lusk its a great person to ask questions on this and has done the Direct Connection style K frame.