Hesitation after Intake Gasket Change

Had an intake gasket leak and changed intkae gaskets last weekend. Now that I've done that I'm getting hesitation when standing on it. Set carb a little richer but still getting it.

Here is what I checked:

1. Timing - had it at 10 degrees over stock but was getting starter overheating. At stock I was getting backfiring so bumped to 2 degrees over stock - still hesitation but not as bad.
2. Check all wires routed okay.
3. Checked No vacuum leaks.

Things I did different when changing manifold included:
1. Ran flame thower and electric choke on seperate igntion wires. Was not getting full 12 to flame thrower - was only getting 8 volts. On my car pertronix called for bypassing resistor wire and get full 12. Ran electric choke to solenoid.
2. Used gasket plugs (came with edelbrocks) to plug ports under carburator on manifold. Told it would run car cooler.
3. Had heat instulator spacer between sapcer and manifold. replaced with a slightly thinner one.

I have a 1970, 302, pertronix ignition & flame thrower coil, with performer edelbrock. Any suggestions on what I should check next would be appreciated - hate having hesitation on take off - did not have before swap.

Thanks

No water in the oil . Checked for vaccum leaks - could not find one, Vaccum looked good on car. Needle ws steady. Put a bigger squiter on accelerator - still same - set idle/fuel with vaccum gauge. Drop car off with local wrench - suppose to be good with fords - we'll see.