would like to know more about my 340

This is an interesting case.

Your block was cast on 11-17-69.

Your engine was assembled in the 1970 model year at Windsor engine assembly plant somewhere near the middle of the model year. Your engine build date is 3071. the 1970 model year engine date started on 2895 and ended with 3259.

By the VIN number, the engine was built for a 1971 model year car at Hamtramk Assy plant with the last 6 of the car's VIN 251203.

Your block was cast and machined, and your engine assembled probably within a month of casting the block. But your engine may have sat for 6 months or so after being built at the engine plant and put into a car at the car assembly plant. It may have sat in a bank of engines at the engine plant, and then "reworked"/converted into a 1971 engine after the 71 model year launched.

Does your engine have X or J heads?

Spread bore carb or square bore?


A 1970 340 had a square bore carb. The 1971 340 had the spread bore Carter thermoquad. If your engine was built in middle of 1970 model year, then was sold in 1971 model year, they would have had to change the intake and carb at least before they put it into a 1971 model year car.