Fifth wheel rails

I would bet the hitch mfgs. know what they are doing when they use grade 5 bolts..... Grade 8 bolts are stronger but are more brittle than a grade 5. A grade 5 bolt will bend before it breaks, bending will absorb some of the stress and energy. A grade 8 bolt has no give in it, it hold a bit longer but will break, then it is all over. I would leave them alone.....

I had a 5er blown over on the freeway awhile back. It tore the hitch into little pieces and the grade 5 rail bolts bent a little but didn't break.

Sam