As others have pointed out, you need to determine the model of the distributor. If you read some of the Stickies at the top of this forum, you'll see that the Load-O-matic is not compatible with any other carb other than the carb that came on the car from the factory.
If you have a later model distributor and if you have a timing light, aim it at the timing mark as you rev the engine. Confirm that the timing is advancing and that the distributor advance mechanism is functioning.
The other thing that I would check would be the harmonic balancer. The outer ring of the balancer has a timing mark notch in it. It is not uncommon for the outer ring to slip due to the deteriation of the rubber and glue in the balancer. The mark will slip and when the timing mark lines up with the TDC scale on the block, the #1 cyl will not be at TDC. Therefore any efforts to time the engine using the indicator marks will be futile. To check for TDC, line up the balancer mark and pull the distributor cap. if the rotor is not pointing at or near the #1 terminal of the cap rotate the engine 360 deg to put the engine on the TDC #1 cyl of the compression stroke. Now pull the spark plug of #1 cyl. Get a screw driver and place it into the #1 hole. Have someone help turn the engine over by hand with a wrench on the crank shaft balancer bolt. As you rotate the engine back and forth stop rotating at the point when the piston is at its highest pioint in the cyl. Check to see if the timing mark is lined up at TDC. If it is not at TDC, you may need to purchase and new or rebuilt harmonic balancer. You could also mark the balancer with a new mark and re-time the engine. But realize that the next time you check timing it may slipped again. You could also use vacuum guages to time and set the carbs to maximum vacuum which should also be maximum timing.
Doug