We had a local mechanic who has been gone for many years now. He would overhaul engines and throw the old valves into a pile outside. You wouldn't believe how many of those old valves ended up in tractor hitches. I have no idea what kind of steel the 1940's 50's and 60's valves were made of but they never went to waste. I have never heard of one breaking but I did see several that were bent. My thought is they were along the lines of grade 5 steel maybe a bit better and maybe a bit worse if the valves were older steel.

It's been said that that whatever bolts you use make sure the shank is through the work and the threads are not holding the load. I find it hard to believe that whatever your Toyota is pulling will break even if it's cold rolled steel, but I agree it needs to be safe. I don't see grade 5 as a problem but it's not my hitch. If you want to spend the money for a grade 8 bolt, it's your hitch and it's your money. The diameter and the design is probably more important.

kwg

For liberals and anarchists, power and control is opium, selling envy is the fastest and easiest way to get it. TRR. American conservative. Never trust a white liberal. Malcom X Current NRA member.