I'm re-assembling a 1964 394, and as I'm cleaning the rocker cover bolts, I find there's an Olds rocket logo etched/stamped/cast into the head of each bolt- or does it just say "M I" (em eye).. you decide!

I guess it says M I... excuse me for thinking it was the Olds Rocket logo... LOL!

 

These are bolt manufacturer's markings, and this particular one was used by GM, Ford, and Chrysler in the 1960s. I don't know which manufacturer this was, but this is a page from a Ford bolt ID site. It helpfully does not tell us what "TY-27" means.





This one is from a MoPar site. Also no info on which manufacturer this might be.

 

Thanks for sharing Joe. I didn't know markings on hardware indicated the manufacturer. Some of those other markings are familiar.

 

Those bolt photos are very cool.
Here's 5 different valve cover bolts JUST from my 65 bolt box.

 

Good eye Dave. Thats just plain cool. Good ole merican made hardware.
Thanks for that fastener info Joe.

 

Pete, is the one that says "L" a left hand thread?

 

Nope, the L and L5 are both standard rocker cover bolts Greg.

 

Back in late 80's or early 90's there was a discussion about some government contractors using substandard hardware in some products manufactured for defense industry. It all boiled down to the head stamps on the hardware used. Some hardware was tested and did not meet the strict mil spec requirements of the government. The issue was solved by the contractors using hardware specified by the govt. that had approved head stamps.

 

My favorite has always been the anchor.