5 5/16 = Jack Pot!
It has to be a 413 produced only in '53 and '54. Rated at 171hp @ 3200 and 343 ft lbs at 1500RPM (!) so you sure won't need the 6 speed tranny! I think I saw where Egge has gaskets.
With a mild clean up and some big pipes this will make a noise that will send the rice rockets scurrying for cover. Man, this is gonna be good!

Leif