itstock----have you ever weighed any of the parts???keep in mind that the weights of the available alternators, starters,etc will be pretty much the same, the
oil pumps and distributors the same, front covers/waterpumps fairly close, front dampners the same, flywheels can be anywhere but available at what ever weight you want so in real--the same---it pretty much gets down ti weight of internal rotating parts and the weight of most of the available present day cranks, rods,pistons are pretty close--------
I'm thinking that most of this misconception comes from looking at iron head/manifold FEs compared to the 289/302 small blocks and not the much heavier 351w blocks----
But-------I've weighed lots of parts over the years--------and the huge differances that people speak of is sorta like comparing camels to horses------------