Cylinder Head ID - Casting and Date Code

toolmanmike said
The Galen books list 3 915 heads,
70-71 360 with 1.88 intake J, Z, or O
70 340 TA with 2.02 intake U or O
72 340/360 with 1.88 intake J

So the never built 70 340's, they were J heads 2.02