HD-E Intake Manifold Difference?

Hey All,

Just wondering if anyone has any clue on the difference between these two intake manifolds for a HD-E. I’m just wondering if there’s any difference between them, is one better/worse and do they both fit the same? I noticed they’re different from car to car, some with one and some with the other. If anyone would be able to provide insight into which is better that’d be fantastic, cheers!

The earlier manifold is typical of the 80s efi, the plenum chamber is tiny but the inlet runners are long, - which helps with bottom end torque.

I don’t know anything about the later manifold as I’ve never had one.
Best thing to do is get both, measure the internal volumes and runner volumes. Compare the cross section of the runners.
Larger plenums are less sensitive to pulses from the inlet valves closing.
There is a poop load of science I don’t yet understand. Maybe Mr Gormsby will chip in and fill in the blanks.