I would keep it simple, put a 4" crank in the 318 you already have to make it a 390" beef up the 904 you already have, you would still have to get a better rear end, you can use a cheap set of headers even a stock iron 4 bbl intake with a good t-quad paint it stock run low 12's hight 11's and tell everyone its a 318. Just a thought!!!!