Engine weight:
Their is a sticky post on dedicated to engine weight
(
Race Engine Weights - Page 2)
Typically they run from about 600-650 lbs (Iron block, alum head and a single carb.)
There is one published Alum block engine at 556 lbs. It is a 598 with 18 bolt “A” heads, big crank, vac pump etc.
With that, a 530lb (maybe less) 550ci BBF is very possible. If it made 850-900 hp,
that’s my version of the Ultimate Cobra motor.
Jason