[wingnut60]

My first thought would be to contact Reese and see what they say about it. My personal feelings would be that if the rails worked before with 4 bolts in the frame, then it may be ok. Perhaps the rails should have been replaced with ones to fit the wider 450 frame? I can tell you the B&W frame hitch for the 450 is different from the 350.

And as far as weakening the frame rail, I don't believe you would have a problem with another 2 holes thru the leg part of the channel--maybe a large hole thru the main part would weaken it, but not a 1/2" hole where there are already some existing. If those 2 holes cause a frame problem, we shouldn't be using that frame to tow these loads.

Joe