Todd: If engine in your truck is orginal, it would have to be either 409 or 396. These 2 engines were the only big block options for 1965. The 427 was not factory truck option until 1968. The 366 was not factory option until 1966.
The number you posted is the ID production number. Need to find the suffix/GM casting number to verify block. Easy ID if block is 396, will have retangular valve covers with 4 bolts outside, and 3 bolts topside. The 409 block has valve covers shaped like upside down W. Get casting numbers and go to:
www.mortec.com This site has suffix/GM casting numbers for both engines, and you will be able to identify. Numbers will be located on lefthand side of block rear, on the bellhousing flange.
Think Chevy!
:rolleyes:
