Looks more like a Ford/Motorcraft ignition module to me. Most GM V-6's and V-8's that used a distributor had an HEI module, which is much much smaller and has connections poking out all over them. The HEI's are mounted inside the massive distributor cap.... as was the ignition coil for many years. I know that the HEI modules have been used on the Lucas distributor in the past, cheap and easily available.
My oil line fix
My 100k stopped odometer fix
Brace for impact, I'm in a "modifying mood". Massive thread count inbound.