Congrats on using the best 4bbl ever made!!
That is certainly a flooding problem that you have. But if only re-built 2 yrs ago, should not need a rebuild kit [ unless it has done huge mileage ].
I would check some other things first:
- fuel pressure. Over 12 psi, is too high, might cause flooding, faulty pump?
- filter. Or quality of. A filter is useless if the element inside is not sealing & lets debris get through to the carb.
Other suggestions;
- Using E fuel? Might not be compatible with n/seats.
- float fuel logged. One fuel logged float is enough to cause BOTH sides to flood
- binding n/seats; binding or rubbing floats; loose n/seats
