I removed my panel body. There were 10 bolts. I used travel trailer tipout screw jacks on all four corners to raise it.

You said you had a replacement '54 frame; Is it a panel or Suburban frame? Pickup frames are missing the panel truck body mounts. They can be fabricated fairly easily however, or you can transfer them over from your cracked frame.
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Panel Truck frame (Small).JPG (67.53 KB, 115 downloads)
20180104_160819 (Small).jpg (80.45 KB, 114 downloads)


1951 Chevy Panel Truck