Help identifying/6

So the stamp on /6 in my 64 dart is T22 12 27 2

This resolves the database conflict, and indicates it's not the original engine to your car.

T: 1963 model year
22: 225 cubic inches (RG engine)
12 27: Engine built 27 December 1962
2: Line or shift code

Stamp # 7225R 2 2 2L
Cast 030-13 (?)

None of this resolves cleanly. It's got elements of how the '77 and '87 engines were supposed to be stamped, but neither is 100%. Could that "L" at the end be a poorly-stamped "E"? Or is it definitely, undoubtedly an "L"? A stamping of 7225R 2 2 2E could reasonably be decoded as 1977-model engine, 225 cubic inches, passenger car engine (vs. truck), 2 February 1977, line/shift 2, cast crankshaft.

But no 7-digit casting number suggests it's a late-late (like '87) block.