Hesitation continues..
So I have been fighting the hesitation for a month now. In the last month i have rebuilt the carb, installed a vacuum guage( runs 18hg at idle), replaced the mech fuel pump and installed a pressure guage (hold steady at 4-5). Bumped the timing up to 10.
Even after all of this the truck will start to surge when it gets above 45 in third or 25 in second. It will pull strong up to this point and then starts bucking. The vacuum will slowly drop from 18 to 5... When you let off the throttle the vacuum shoots back to 20+.. the fuel pressure never drops
In neutral you can run the rpm high and it never stumbles and the vacuum idle hold mostly steady.
I'm now wondering if the carb is at fault, it has a d6g1 carb and it is a 1948 dodge 230 engine. Is the carb wrong for the block? What else could it be? Weak springs would show up while racing in neutral, right? The needle may flutter 1/2 hg in each direction when it is racing but that is all.
I'm at a loss? So are my local car guys.... any thoughts?