Willy, When the problem occours at say 50,if you continue to open it up does the surge go away or does the engine refuse to go faster which it would do if fuel starvation were the problem.
Normally when you try to accelerate beyond the 50 the vacuum would drop and the metering rods would retract calling for more fuel--so if the fuel was there(in the bowl) the mixture would richen-power and speed would increase--but if the fuel level were low because of a deficient delivery(causing the surge), the engine would die and backfire or miss severely because of the increased air/insufficient fuel.
This test will tell you if the fuel delivery is deficient.
Wish could have gone to the car show--I drove by 6 times as I live 1 1/2 miles beyond there.Sometimes just not enough saturday to get er all done.
