Looking for D4B intake Manifold

To answer the D4B -LD4B question, no318 is correct, the bosses the 5/16 intake bolt holes are drilled on are angled more vertical than the LD4B, look like little ramps off the original intake gasket surface. you can drill them out and grind them or run a beefy washer under the intake bolt to fit a 66 and later head. The L is the "Later" head if that helps to remember.