Like your freshman science teacher taught you, isolate only one variable at a time.
I think the the pressure regulator was unnecessary but it didn't hurt. More than likely your float was set right from the factory but had some dirt in the needle/seat or it was stuck open. The problem you're having now is that your float level is too low and when you hit the brakes hard the gas is sloshing to the front of the carburetor bowl and starving the engine of fuel. Try taking it back apart and setting the float level to factory specs and see if that helps.
I have the adjustment data table right in front of me at the moment. Your float level should be 1-9/32" which is measured from the gasket surface to the bottom of the float in the "closed" position. In the "open" position it should hang down 1-3/4"
Hope this helps amd let us know how ya make out
