The 250/292 engines are the 3rd generation of 6 cylinder made by Chevrolet. The 1st generation was the pre-1937 engine, then the 1937-1962 Sovebolt was the 2nd generation, and then finally the 194-292 engine group being the 3rd generation. The Atlas engines now being the 4th generation. Im fixing to get prototype samples of my 2 pc cover cast now, so barring any tweaking to the patterns, they should be available shortly.
