ID THIS BLOCK

'64 Dart said
Forgive my ignorance, on the deck where the displacement is stamped it followed by the letter 'R'. If it was a hydraulic lifter motor wouldn't it be stamped 'E'?

Both stampings are present: 9225R 3 9 E

9 = 1979 model year
225 = 225 engine
R = Regular gasoline fuel
3 9 = Assembled on 9 March 1979
E = Cast crankshaft