Seeking advice intake manifold

I’m with the use what you have crowd.

Nothing wrong with what you have, and to find some improvement there will require more than just a manifold change.
...and then the snowball effect takes hold- I should get better heads to take advantage of the manifold's increased flow, a cam to compliment them, more compression and a TC to take advantage of the cam... then suddenly you're just ordering a 408 Blueprint motor... and diving into the rear end and suspension to get it to hook up...