The hardtop frame will have one additional body mount bracket on the inboard side of the rail right at the B-pillar. If your using the hardtop frame on the sedan, just remove that bracket. If you putting a sedan frame under a hardtop, switch the bracket fron the hardtop frame to the sedan frame.
’55 & 56 frames are identical except they have different rear spring hangers. ’56 has a small gusset welded into the rear box portion on each side.
’57 frames have different front horns for the bumper mount. I don’t know about the rear spring hangers.
Convertible frames have an x-member welded into the middle for stability.
Hardtops have the extra support as noted.
Some frames are ‘one-piece’ and some have welded seams but are identical mechanically.
A ’56 2 door will fit on a ’55 frame for a four door, etc. All years and styles have the exact same wheelbase. 115 inches.
A forum community dedicated to 1955, 1956, and 1957 Chevy owners and enthusiasts. Come join the discussion about restoration, engine swaps, reviews, performance, modifications, classifieds, troubleshooting, maintenance, and more! Open to all models including Belair, 210, 150, Sedans, and Nomads.