I need a "squirrel basket" for RGAA150G vertical furnace (installed in 1976). It makes racket when it first
Comes on and then quiets down after blower is going about 15 seconds. I replaced the fan motor but the repairman says they not longer make the part for squirrel basket.

What part? Bearing? Most bearings are not only for 1 fan, you can buy replacement bearings from a number of places. If it is the bearing, remove it and look at the numbers on the side and cross reference it.