[SS396Convert66]

Mrpaticular The 2 letter code thing through me off for about 10 years. I know for sure that all chevy engines before 70 had two letters. the engine in my 66 had 3 letter so I know it could not be orig. The engine in my 66 had 3 letters EDH. then in the 80s I talk to a old engine builder working on another engine for me. I ask him about my code and he ask if it had a holley intake I said yes and he said the H stands for holley could have had a Q after the ED also. So after10 years of thinking it was not numbers matching to matching numbers. Back then we did not have Team Chevelle.