4- barrel for a 306, check specs & comment

[Caprimaniac]

Hi. I'm rebuilding a long rod 306 "economy".
I thought getting an inlet + carb for this enginge, but have no experience on 4- barrel carbs (only webers). Engine should be a little de-tuned compared to the current 347 solid roller, a little more street friendly, but still racey. will shift at 7000- 7500.

Let's see:
- 1982 block, 030 over & crank
- Eagle SIR 5.4" rods and KB 746 pop-up pistons
- Solid cam, for instance comp 31-366 or 31- 335
- Some kind of cheepo aluminium heads. Not sure what yet. found RHS heads @ 439$ each complete, but turns out a misprint... Another option is to upgrade my Vic Jr's on the 347 to something even "better" and put them on the 306.
- Weiand X-CELerator single plane manifold
- Holley 650 DP w/ mech. secondaries (4150 street HP series, HLY-O-82651), Proform ditto (PRO-67199) or AED HO series 650 (AED-650HO)

This inlet seems to do what I need it to do and even fit under the hood. Problem is the carb. I guess 650 cfm is enough for a 306 @ 7000 rpm?
Have some of you fitted any of these carbs to a 302 and found it to be "correct enough" jetted to suit this application? The less fiddle to fin dcorrects jets etc, the better. I also wonder what kind of adjustment can be done to these carbs without changing the jet. Can the mech. secondaries be adjusted?
Ok, now I feel a little guilty... Will check the websites to look at specs & tunability of these carbs...

Thank you

RS