Not much known beyond that it was in Pennsylvania for a long time, and has 52,000 miles, appears legit on that front from the immaculate interior. All casting and stamped numbers make sense, being from late 1972 or otherwise appropriate. Just had the TH400 overhauled, guy said there was no real wear, just deteriorated rubber seals. The engine was opened on the bottom at some point, the rods and main caps are all number stamped and there are screwdriver witness marks on the oil pump cover. The pieces (bearings, pistons, etc) are stamped or cast GM with no undersize designators though, so maybe it was dealer serviced for something early on, not sure. There is rust, mostly in the floors (shocking), so if you read this and know a good shop near NYC shoot me a PM please!
1973 Chevrolet Malibu (Midnight Green)
Factory LS4 454, TH400