Whistle while you,,,, drive?

Throttle shaft is a good thing to check, same with the PCV.

Might also be worth looking at any vacuum caps you have on the carb. Seems like they don’t make them like they used to, I’ve had to replace several as they’ve developed cracks after not all that long. Probably a fuel additive problem. Or maybe just crap rubber. Either way, I’ve had multiple vacuum cap failures so if you’ve got any check them.