7181 looks like a datecode for 1971, which would mean Amelco/Teledyne 300 series "HNIL" (High Noise Immunity Logic, a DTL variant) looks about the right timeframe; 311 is an RST flip-flop and at least the number of pins on the package lines up. I've attached some more info on that family, and since it has a schematic of the 311 you can try to test the pins with a multimeter and see if that also matches.
(Source is "Anglo-American Micro-electronics Data 1968-69", which is basically one huge databook; the whole thing can be found at the usual places online if you're curious.)