I am a "NEWBIE" here, but built many a diesel and chevy engine. Over 30 years fixin diesels. Best bet is to figure out where the leak came from. Flush the radiator, head and block out when apart. It seems you know it came from the head gasket. You should be able to see where the leak was by looking at the head gasket or block or head as to where the leak started.
I have just got a '87 tin top. rebuilding a week motor. Got the gaskets, pistons, bearings, new exhaust valves, new heavy duty clutch and a new rear seal waiting for me at Petroworks in Fallbrook. They are just 20 miles from here in San Marcos, CA. Picking the stuff Saturday morning, hope by Sunday afternoon if the NASCAR race does not distract me to have it ready to bolt in!!!