I know someone with one that's olympic gold / original owner - changed the cam to hydraulic roller - way better power band and no valve adjustments - he also swapped the points distributor for an HEI unit
Timing effects dwell but dwell does not effect timing so check the points and condenser that would be the first place I'd look As a matter of fact just to eliminate the whole points issue I'd of course save the original distributor but swap in a nice quality hei unit and then see how she runs 90 percent of people's carburetor issues are not carb issues at all but timing and of course before 73 dwell issues hence the hei distributor came into play I'm not a gambling man but I'd be willing to bet on your problems being distributor and not carb
Factory ignition timing was specified low so it would pass emissions and so the owner wouldn’t blow the engine up. Set initial to 14* which should equate to 36* at 3000 rpm if you have a back dial timing light. Timing is set with the vacuum hose off the vacuum advance can and plugged with a golf tee. Secondary throttle stop screw adjustment Must have carb off car. Set as follows: Back off adjustment screw until the throttle plates are fully closed (secondaries). Turn adjustment screw until it just touches the throttle lever and turn 1/2 turn more to position the valves. Don’t listen to the know it all dreamers. Leave the smog on. I tested my 70 Z28 with and without the smog. No big difference.😮
1) the TUBES don't affect the way it RUNS 2) One can simply remove the tubes...remove the injection manifolds and plug the holes with pipe plugs...OR...only remove the tubes 3) he SAID he wants to KEEP IT ALL ORIGINAL