All depends on the parts really. A forged 4" crank and H beams are heavier... most other racey parts are lighter. I've always used 60lbs for small block to B wedge, and 150lbs from small block to RB wedge similarly built as a guide. /6 and B wedge weigh fairly to the same too. If the guy has cast manifolds, AC, options, etc.... then it could be a lot heavier. My buddy's Cuda went 4100lbs w/o driver with Dana, Hemi 4sp, iron 6bbl, AC, PW, shaker, etc.
