Is this a street/strip car? If so don't do the iron head and mixing fuel Your far better off selling the 516 and appling that money towards a good set of alumimun heads like the Eddy RPM I have had a bunch of different BB Mopar engine combinations, the Eddy RPM heads( out of the box) outflow the Mopar productions so much more that it is a waste of money, IMO, to spend money trying to use the old Mopar iron heads