I needed to replace the throttle shaft bushings on a Rochester Quadrajet. I know, everybody does as well.
But I’m cheap.
Actually a pretty simple tool: 3/8″ rod machined down to 5/16″ to pilot the cutter by the center bushing location. Flutes cut with a Zip Disc. Back rake cut with a file. Works well enough to cut aluminum.
Bushings tapped in with a hammer, using a 5/16″ bolt as a driver.