Engine casting numbers?

['69FuryIIIConvertible]

First off, what was the last year that trucks had Forged cranks?

I ask because what I have here appears to be a late 1975 440 with a forged crank.

Casting date is 9/26/75, block number is 4006630-440-10

On the pad above the rail it has 6C122042

Top pad shows 6T440 F
below that is 12 4

Any help is appreciated.

Nick

 

[69CoronetRT]

I can't speak to the trucks but the 6C122042 stamping is the serial number for a '76 C body built at the Jefferson plant.

Here's the decode info for 1975 but the same concepts apply for 1976. 12 4 (December 4th 1975)is the assembly date