Ready to shoot my 273

Without a lean/rich indicator (O2 sensor) you are flying blind, so consider getting one eventually.

Your not totally bind, once too lean you can feel it while driving, then richen it up a bit. For the secondary jetting go for highest mph in a run. Keep jetting up till power feels to drop then back it off 2--3 jet sizes. Gets you close with no 02 sensor

Right now something is way wrong, its not close at all. I agree its in the carb likely, floats are a good maybe, could be leaking, sticking or set wrong.