A good quality medium stall ~3200 rpm converter (like a 10" Turbo action) would work wonders, I'd do that first and then the gears only if you're still not happy....my feeling is that may be all you need. A good street-strip shift improver kit can also help noticably with vacuum secondary carbs.

Which 292 Purple shaft is it? is it the 108 or 112 lobe seperation? for a heavy car with mid 3 gears I would put the 108 in at 105 and the 112 in at 107 Intake centerline.

Lighter diaphagm springs (spring quick change kits are cheap and vey handy for tuning) should help and make sure you have adequate fuel pump pressure and volume.

Please define 'weigh 40 mail' for us ....I love your phrases for the 'heads' and 'headers' and especially:

Current Interrupter = Distributor!!