Cylinder Head ID - Casting and Date Code

[toolmanmike]

The chart does not contain all the information.

The X heads were used into the 1970 model year, but not for all of the 1970 model year.

There are plenty of 1970 340s out there with 915 heads.

Agree. The info on the charts is probably correct but like you said, incomplete.

 

[70 Buster 340]

I think the heads pictured in the first thread are regular 1971 car model year (cast Oct. 70) 340/275hp 2.02 J heads.

The charts are incomplete and thus can be considered inaccurate by default.