I thought I recognized those head numbers. I have the 3973487X heads that are 2.02's. Lingenfelter book says that my 487X heads are great flowing. Check out this site for the break down on some of the different head configurations for performance small block chevy heads.
Small Block Chevy Heads
This is what is says about your heads.
LARGE CHAMBER PRODUCTION "ON CAR" HEADS
"487" – 3973487, OR 3973487X. The regular casting was found on the 1971-1972 350 LT-1 engines, had 1.94/1.50" valves, 76CC combustion chambers, DO have accessory holes, intake port volume should be 161CC's, exhaust port volume should be 65CC's. The 487X had 2.02/1.60" valves.