Standards form the basis of all engineering tasks. For a listing of Irwin standards prior to 1980:
Irwins 28, 30, 34, and 39
Irwins 37, 42, 43, 44, and 52
As with any long lasting engineering program, changes were made during the life-cycle of the product. Please check with Gene regarding updates and later production runs. He can also provide advice on suitable substitutions for items no longer available.