According to Leo Santucci's Inline Six power manual, your block is a '68-'88. The location of the dipstick tells this much. With out a number stamp to identify it, next option is to check the stroke. Pull one spark plug out and stick a long narrow stick down the hole and rotate the engine slowly till the piston hits bottom. A 230 ci has 3.250" stroke, the 250 has a 3.530" stroke, a good 1/4" longer. The 194 went out of production in 1967 so I would rule that out.
joe
