About the LD4 in 1978. The only difference that I know of is the valve cover is not the wide one like in 75,76 and possibly some 77s. I am not sure when the heat riser valve was replaced with an EFE valve that is controlled by vacuum . In 79 car engines went back to a separate head and intake, truck engines got the new 2bbl intergrated head with a split manifold. I believe that the short block and camshaft are the same for all three engines. Why did car engines go back to a separate intake for one year has always been a mystery to me. Anyone know why? Jay 6155
