Ports and fitment are the same. The only possible issue is that the 390327 intake only has one sensor port in the water crossover; the correct 398663 intake has two - the second was used for the thermal vacuum switch controlling vacuum advance in some applications.

 

 

The distributor has nothing to do with the need for the second port. Olds used a TVS on some cars to switch from ported to manifold vacuum if the engine started to overheat. If you are using straight manifold vacuum for the advance anyway, that's a moot point.

I question your desire to change the manifold, however. The HEI isn't "period correct" either. And frankly, if your goal is to just hide the late model E-brock intake, I'd simply grind off the logo, sandblast to eliminate the grinder marks, and paint the aluminum intake engine color.