Carter AFB

I would check the main throttle shaft for wear, if it has wiggle and play in it a rebuild may not help much, it will suck air, But there may be a way to repair this.
I had one on a 383 years ago and packed the shaft with grease when I first got it and ran good. My self I like the old AFB Carters
I hope a good tech will jump in here and help you find the # location and advise you on where to find it.