Edelbrock Performer vs Edelbrock RPM Airgap

So just wondering if a swap from my Edelbrock Performer manifold to and Edelbrock RPM Airgap would make any noticeable difference in performance. Or maybe at lease help with vapor lock issues during the summer.?

My current setup:
'71 model 318 - 30 over
Machine shop got the pistons for me, they said the engine should be about 9:1 compression
340 auto cam
Heads are later model U heads, suppost to be 318-4bbl heads. They have 1.60 - 1.88 valves
Edelbrock Performer manifold
Edelbrock 1406 4bbl carb
Early 340 exhaust manifolds
Dual 2-1/4" exhaust with H pipe, Walker quietflow muffs
Stock 904 Automatic
8-3/4 rear with 3:23's
26" rear tires

Runs good, but just seems a little sluggish. Not really crisp throttle response.
Planning on getting a wideband 02 gauge/sensor so I can get the carb dialed in better. But was also maybe thinking of a cam and manifold change.

Your thoughts on the Airgap ?
And would a more modern cam grind wake this thing up a little?