Time for a confession. Me + Slants = reasonably well informed. Me + Small Block = mostly clueless. I didn't know there was a choice of early/late for water pumps. The core engine is in a 74 Dart but it needs a thorough go-through so if it fits I can use the early water pump. The radiator is a Summit 22" that is not all that thick - it's about the same as a 2-row stocker. I can get a measurement on the radiator tomorrow after work. The clutch fan I'm looking at is 3-3/8" deep from flange to front of clutch.