Confederate,The marine motor will work but they are usally low compression and low HP.You will have to change ,intake,exhaust manifolds,Water pumps and a few other parts to make it work.If you use a 460 out of 2wd you will need a new oil pan to clear your steering.
If you can find a 351 Cleveland motor to build you can get plenty of power cheaper than building a 460 or the 351 M.