on the 450, 65 with 4.30s and 33.4 inch tires is 2150
on the 250, 65 with 3.55s and 34 inch tires is 1700 (factory)
on the 250, 65 with 4.10s and 35.5 inch tires is 2000 (now)
these are all ovserved on factory gauges, so, they are that accurate..... LOL
i would imagine 3.73 is about 1850-1900 with 34 inch tires, but I never had 3.73s, so I cant say for sure, the others are #s that I have had before, or currently have.
I looked into using lower gears, like 3.73s on the 450... problem is, that is a dana 110, and gearsets for that monster are over 2,000 bones.... and if I dont like it, i am stuck with it. I got my GV for 1600 bones, new, and it will likely cost about 600 bones to install. Then, I will have MY CHOICE of what RPM I wanna cruise in... for towing, I would hate to have my 5th wheel, 18,000 lbs, up hill, in the mountains, at 55 mph speed limit with 3.73s.... with my 4.30s, that scenario is no problem... 32-34 lbs of boost, 1450 egt, maybe creep up to 1550 towards the end of the hill, but I dont mind hitting #s like that for short time frames. same scenario with 3.73s, I dont think OD would hold, and if it did, egts would likely be much higher. I just want another gear for light loads, or empty running. It is supposed to drop rpm by 400-500, depending on your current gear set.