For what it's worth and for what you're paying for , I swapped a bone stock 273/904 2 bbl iron manifolds a/c p/s etc. I installed a 440/727 with aluminum water pump housing, water pump, intake manifold, cylinder heads removed the a/c system up to the firewall and im running headers of course. I did not touch the torsion bar settings and the front end of my '67 Satellite was noticeably higher than before the swap. I dont know the difference in weight but i can imagine it must be substantial to be a visible difference, kinda like when my overweight date gets out and my tires dont rub anymore noticeable lol.
Copper