PART NO. SPL.PAGE DESCRIPTION
AEH195 15.A.16 Nut for stud (3) -(exhaust pipe flange, exhaust manifold, eng.unit, 1500)
AEH195 16.A.15 Nut stud (3) -(exhaust pipe flange, inl+exh manifold, eng.unit, 1600)
AEH195 TC.A.21 Nut for stud (6) -(outlet flange, exh.manifold, engine, Twin Cam)
Item 14 in the image above, this is a 3/8-24-UNF fine thread, extra length brass nut.. The special drawing number is due to extra (non-standard) thread length, and possibly a harder than standard brass material.
For reference, item 18 is a 5/16-24-UNF long brass nut. This one also has a special drawing number, but in this case very special. The original factory supplied manifold to head nuts had a stainless steel thread insert molded into a brass nut. These would be exceedingly expensive if they were still made. You will likely not be able to find them anywhere in the world now.
Brass nuts commonly supplied are often soft brass and too easy to strip the threads. I will settle for using stainless steel nuts and doublenutting the bottom studs.
|
Item 14 in the image above, this is a 3/8-24-UNF fine thread, extra length brass nut.. The special drawing number is due to extra (non-standard) thread length, and possibly a harder than standard brass material. 
