Always verify that the ignition is spot on before looking to carburetion, even if your experience tells you otherwise.
"Running rough" (missing) is generally (I did not say always) caused by faulty ignition, but it is nearly impossible to diagnose such symptoms in a chat forum.
Is it flooding? Black smoke? If so, look to float level. The OEM Holley carburetor is very sensitive to float adjustment.
Does it stumble only upon tip-in (throttle up)? If so, look to the vacuum operated accelerator pump and the usually defective vacuum advance motor, which affects intake manifold vacuum.
Many folks, herein, do not like the Holley carburetor used on Ford tractors but it was a very good carburetor in it's day, and quite simple as compared to contemporary automotive carburetors. Should you decide to rebuild yours, bite the bullet and buy your overhaul kit from a CNH dealer. Insist upon the expensive genuine CNH kit rather than an aftermarket kit and pay close attention to the float level and float drop adjustments. Be certain to take both tractor SN and carburetor SN with you when you visit your CNH dealer to order your kit (they will NOT have one in stock) and insist upon speaking with an experienced parts person.
Finally, disassemble your carburetor before ordering your kit. Some (many?) Holley carburetors cannot be cost effectively overhauled due to, e.g., corrosion damage. If this is the case with your carburetor, you will need to replace it with a Zenith.