Currently doing so in my 63, there are alot of forums based on the swap, I am doing a 4.6 and doing a rwd conversion on it using a 2.8l 700r4 tranny. People who have done the swap have reported gettign 25-26 mpg on big boats such as ours... that is why I am doing it. check out a site called
www.chrfab.com or .net they have everything u will need, and some badass billet valve covers and a forum. use a stand alone ecu