400 vs 400 HP What is different between the two?

[Charger1973]

What is different between a 400 and a 400 HP?

[Nacho-RT74]

HP is magnum:

-windage tray
-HP exhaust manifolds
-HP camshaft, however camshaft list doesn't list a 74 HP cam
-and MY magnum got double valve springs, but I have read that wasn't really part of 400 magnums, just 383s and earliers 440s... dunno thought

[69CoronetRT]

.

[Charger1973]

Eventually I want to turn my 400 into a 451.  So, there is nothing I really need from a 400 Magnum then.  Only asking because I have one here I could get some parts from.  Exhaust manifolds maybe, but I plan to run headers...

[Nacho-RT74]

of course I forgott the 4 bbls spreadbore manifold

[Bob]

So 400 Magnum decals on mine would not be a lie. A couple years ago I think Chryco said the same thing about the differences. Good refresher.
Bob