note that just because its a D4 block (1974), does not mean the engine was assembled and installed in a 1974 vehicle. Casting numbers were used until a revision was made that created the need for a new casting number. Generally, a 74 block might have 77 heads, 76 intake, and a 79 carburetor. In that case, you could assume that the engine was assembled and installed the year of the most recent casting number.
basically, what you've got is a standard issue 302, likely with the crappy low compression heads, dished pistons, and retarded timing set.