When did the 400 big block engines become available?
A little history on the 400 big block engine. The 396 debuted in mid 1965, and was run through the 1969 model year. In 1970, it was still billed as a 396, but was actually bored .030 bigger at the factory to 402. In 1971, it was sold as a 400, which was the cause of much confusion because of the 400 SB that also came out in 1970. An easy way to identify it is by the balancer. A 454 in externally balanced and the balancer is not evenly weighted all the way around, where as the short-stroke 396/402/427 all used the same crank & balancer. It’s smooth and evenly weighted. In a vehicle as old as this 1972 is, it’s quite possible that the original 402 was replaced with a 454 due to the fact they are easier to come by than the 402 is these days. NOTE (not from Devin): With the introduction of the LSx motors in the late 90’s, all big block motors are doomed to become obsolete in the near future, with the exception of certain racing & marine applications. With their cost of parts, weight, opera
