Not sure if the Jetstar has the same spindles as a "65" Cutlass (perhaps one of the experts will chime in) but if it is try
www.paddockparts.com. They claim to have true bolt on kits for a "65" Cutlass. If you find out they are the same and do it, let me know how it turns out as I'd like to do my car (Cutlass) in a few months.