Went to Pullapart a couple of years ago, found nothing that I had to have. Rather than go home empty handed, I stripped bolts and nuts from pre 70 FoMoCo stuff. Lots of 1/4, 3/8, 7/16, and 1/2". Nice smooth threads, all of it looked pretty damn good to me. The guy at the counter just shook his head, didn't charge me anything. I'd like to use it wherever I can, but wondered if OEM from mainly the 60s was low bid cheap, or decent grade and strength. Obviously some of it has to be stronger and some, not so much. All of it's been installed only once, and even the heads looked better to me than what I can buy locally. I admit to being anal about this, but I deal with Chinese stuff all day, and would much rather use old USA than new Asia on my projects. What say the HAMB?
The OEM quality is pretty high, with better QC than much of the new offshore produced stuff you buy new. The main difference is that the old bolts will have a variety of corrosion protection finishes, whereas the new stuff is going to be mostly zinc. Some of the special bolts used by the OEM may not have the strength level on the head, so if in question use a bolt with known marking and strength. I always try to save bolts from projects or the stuff I remove at the junkyard. Not only because I like the OEM bolts for style and appearance, but it also saves a bunch of money and trips to the store.
he OEM bolts are a better quality bolt than you can buy at Menards, Ace hardware etc. Fastenal and other bolt suppliers have quality bolts. I have a container with all pre-49 Ford bolts harvested from chassis and running gears like trans, engine, springs etc etc. They have a thicker head on them, are predominately fine threaded and have beautifully rolled threads....lot of 'em have holes drilled for cotter keys. I de-rusted them in vinegar and put the container up for sale at the last swap meet.......the young guys thought it was hilarious I was selling used bolts! Especially ones with NO markings on the heads! I haven't tested them but I believe they're grade 8 bolts.
the only problem I have with old bolts is that the finish is usually in poor shape by now. But they are good bolts. I use old stuff when I can.
I've used over lots of my Ford hardware, dump it into my citric acid bath for a few days and it comes out clean. The heads I'll paint with VHT spray paint, use never seize on the threads and call it good. The body bolts & nuts are all flanged and fine thread.