The seats in the Corvair were the stock buckets. They are nice looking seats but have zero side support, and the upholstery was shot to boot. Clark's sells excellent repro upholstery, but I wanted some side bolsters and didn't want to rebuild the stock seats. In typical "wallet hotrodder" fashion, I bought a set of generic seats. They are Procar brand black vinyl and match the stock upholstery stitch patterns well.
While I was at it, I installed three point belts. These are three point aftermarket belts for a 67 Camaro. They fit the 66 Corvair perfectly. The stock lap belt, while 100% legal, was a constant source of worry.