I use an M10x1.5x45 (10.8 hardened) bolt all the time. I buy them at Farm & Home in their bulk bin.

 

I looked for new sources of these for the poster and did find but didn't both saving link, The only source I found wanted 39 dollar each for them new lol.

 

Wow, kind of like they're a ******* scam?

I'd be willing to wager that some tool/ die company came up with this design, talked-up a GM exec, and once the check cleared, then GM bought a few thousand of these shitty bolts.
Why don't they use them on the 6LXX transmissions? Why isn't everyone else using them? Has ANYONE seen them ANYWHERE ELSE?

I'm sorry, but this kind of stuff makes me irrationally angry.

 

If I could find some sucker to buy the ones I have for $39 each I’d sell them and use hex head bolts.