[Mr. P-Body]

There are others out there, too, with good offerings for Pontiacs. P-Dude is one. We use his pistons for the 4" stroke engines.
I agree, the KRE d-ports would be the better choice for a streeter. For a 406 CID (.030 over 400) engine, I would stick to the "285" version (advertised intake port flow in CFM). The 310s would be a tad much. The HSC chamber (High Swirl Combustion) makes tuning for pump gas a bit easier. Jeff Kauffman or Cliff Ruggles can explain it in detail.

Now, a couple of myths to bang on... "You can run a bit higher compression with aluminum". True enough, but that's not the whole story. You MUST run higher compression with aluminum to achieve the same power, all other factors being equal. The reason is that is aluminum "soaks" a lot of the heat out of the combustion process, making it less efficient. By increasing the compression, you get back some of that efficiency.

Edelbrock heads are only similar to the old factory Ram Air heads when it comes to intake and exhaust flanges. They are NOT "old technology". The intake port is fairly close, but if it ain't broke, DON'T FIX IT! The size (and therefore volume) of the port is really the significant difference between the stocker the E-head. The exhaust port is an entirely different matter. The "D" shape (not to be confused with Pontiac "d-port") has a round roof and flat floor. This is current port convention for high performance engines, regardless of family. With some judicious porting, the exhaust port can be made to "work" very well, despite the "droop nose".

All this is well and good, but if the bottom end is not upgraded to take the power the top end supplies, you're gonna have to replace it ALL again...
Edelbrock cams are generic in nature., That is, they are the same grinds all the other non-cam grinders are selling. Modern cam technology has past them by long ago. Comp and Crower are the leaders today. I understand Lunati is selling some of the old UltraDyne grinds, as is Bullit. For streeters, it's pretty hard to argue with the Comp XE series. If you can get a definitive "yes or no" from either Lunati or Bullit about the UD grinds, they would be among the better choices (provided it was "yes"). PIN THEM DOWN...
FWIW

Jim