BBC vs SBC motor mounts - they are not the same

[Mr.Chevy4x4]

Well, after much fussing, cussing, and general aggravation....it finally dawned on me what my header fitment issue was. I pulled out a set of known SBC mounts (engine side) and compared them to the BBC mounts that were on my fresh engine. I know these to be original big block because I know the truck the engine came out of. So if anyone ever tells you they are the same...send them to this thread.

Shiny on left is BBC and dull on right is SBC. There is almost exactly 1/2 inch difference in the two. This half inch sitting lower in the frame and sagging rubber mounts have been the problem the entire time.

Mike