Streetmaster 318 vs. Performer for street use

Hi

I´ve got a 318 with:

Edelbrock Perfromer Plus cam and a Holley 4160 600 CFM carb. Hooker headers.

At the moment it has a Streetmaster 318 on it which looks very new even though I know these haven't been produced for a while. Perhaps it was old stock. It's a single plane so I wonder...

My 1st question:

For street use and off the line performance is it worth switching the Streetmaster 318 (single plane) out for an Edelbrock Performer (dual plane)?

If so by what kind of margin? I realize a dual plane results in more low end torque but how much more with these specific two. The Streetmaster has narrower runners to maintain velocity but it's single plane....

2nd question:

a:

The Holley stumbles off the line at WOT, just a 1/4th second or so then takes off. Only happens if I plant the pedal. Bad power valve?

b:

Also in Reverse, if I give a litte punch of gas and let go and engine stalls. Could the two be related? Verry irritating when parking!

I run 95 octane pump gas, stock electonic dizzy with vac. advance (ported vac.) set at 10* BTDC with hose disconnected at idle.

Holley Idle Screws set at 3 turns out (Holley's advised starting point) and idles very well.

Thirdly:

This is kind of a rhetorical question but:

Is it 'normal' that when not fully warm/cold I punch the throttle by hand at the carb for a short burst (as short as possible, like a jab) that it bogs? Could this also be related to the Holley having vac. secondaries that only open under load?

Thanks!

David