What happens if you choke it? I'd suggest doing a fuel pump capacity test, where the fuel line at the carb is disconnected and put into a catch container. 30 seconds at idle speed should produce ay least a pint of fuel. If not, start looking for line restrictions or a bad (even if it is new) fuel pump. If you get good volume- - - -the problem is in the carburetor.
Jerry

Edit: a low float level will produce those symptoms as the power valve opens and the carb starts drawing the max fuel flow in 3rd. or 4th. gear and empties the float bowl.

Last edited by Hotrod Lincoln; 07/31/2014 10:13 PM.
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