Carter carb tuning help
You can richen these carbs up by changing the rods that go into the jets.
I would want to check the mechcanical advance on the dist with a timing light -- need a total advance of aprox 32 degrees or so (excluding vacuum advance). At WOT, vacuum is close to zero and thus no vacuum advance on hard acell.
Most likely not an issue, but keep engine breathing in mind. Unrestrictive intake and exhaust are needed for good power. The problem started after the carb overhaul, so unless something has changed in the intake or exhaust, these are most likey fine -- but they are part of the picture.
Fuel pressure and volume are another thing to put on your check list.
Are you running points type ignition? They may have worn closed a little.
Is the carb the only thing that has changed?
Good luck.
Brian