streeter, the 348 was introduced in 1958 and was the first big block motor. It was complimented a couple of years later with its big brother, the 409. I left them out of the lineup because you seldom see one of them anymore, unless it is in a restored Impala. The 409/4-spd. was probably the first Chevy muscle car motor/trans. Although it was basically a truck engine, Chevy offered them in the Impala from '61 to '65.