Harbor Freight has the 1-60 set, they are imported but good enough in quality to get the job done. They are around $20 per set.
The 61-87 bit sets are harder to find these days, and insist on American made ones. We were selling the bit sets for a while, but folks didn't want to pay the price for the American made sets, so we dropped them from the inventory.
Tough to justify nearly $90 for the 1-60 and 61-87 bits just to do one or two carburetors, so I really don't blame them for going for the offshore bits. You can get all 87 bits for under $40.....Cliff