I was installing my 383 in my 72 last night when I ran into a problem. My car came with a 307 and I went to the parts store to buy mounts. I bought mounts for a 72 350. The block mounts will not fit over the sub-frame mounts. I thought all 72 small block mounts were the same but they are not. I went back to the parts store and bought 307 mounts - they are different. Has anyone ran into motor mount problems before?