Now that 6 years has gone by, Wylie has probably moved on.

But, frame size and strength is worth discussing and is just as confusing. The 3 sizes are 6, 7 or 8 inch height, with various thickness.

Best I've been able to determine, 6 inch was used up to 7700 gvw, 7 inch above 8000. The 8 inch got common with the diesel trucks but there's minimal correlation to engine. Rumor is that lots of club cab gas trucks had 8 inch.

I've worked on an 89 W250 Cummins with a 6 inch frame, had an 89 W350 cab and chassis gas 10k gvw with a 7 inch, a 77 W200 8k 7 inch and a 92 D250 Cummins 8500gvw and an 8 inch frame. Other trucks I've owned were under 8000gvw and 6 inch.

The 92 Cummins is odd, it's got the heaviest frame but a lighter rear axle and no overloads compared with the 89 cc. The 92 window sticker does call out an 8500 gvw package which might be the frame upgrade.