The 915 heads with 2.02 valves were 70 only for the T/A and the 915 heads with 1.88 valves were 71-72 340 heads. The 73 340 heads had a casting number of 3671587http://www.
There were a lot of 2.02 valves in 915 heads, most "71" 340's had 2.02 915 heads. 340's went to 1.88 intake valves when they dropped compression in "72".
