you are right, from what iv read they start to defuel by about 2200, i cruise around 2500 to maintain 70mph. 80mph is a struggle.

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the chevy makes around 550hp and torque. it has more power then the cummins by far, torque may be about the same, definitely not delivered in the same manner tho. its just a lighter truck and i dont use 4x4 to avoid grenading the front diff, the last peice of half ton equipment left on that truck . its a fun truck to rag on, it always puts on a good show as long as you dont touch 4x4. i was and still am really surprised i had any trouble with the dodge, i realy beat the crap out of this truck and it simply never breaks, always runs good, gets me were i need to go and goes offroading on the weekends too. the chevy may never break anything serious but its like driving a race car around, always little issues, hard starting, burning up spark plug wires, headers leeking, ect, ect, its just a headache to maintain such a truck.

its hard to even get the motivation to work on the dodge because it ALWAYS runs and gets me where i need to go no matter what. i dont want to even mess with the truck.

 

I have the same problem with my 4.10 gears. Gotta find some top end. Going to look into the gsk upgrades

 

i got a 97 3500 dually with 3.55s in it i believe, and 90 is about as much as your going to get outta her. but like you said 80 and im about to the floor

 

I would think with 3.55's you should be able to get 100. With an NV4500, 3.55's, and 30 inch tires my Ford will hit 99. If you had 31's or 32's that number would even go up a little bit.

 

you maybe right, but im pretty sure 90 to 95 ill be pushin close to 3000. Ill check it out tomorrow

 

honestly if you add everything up on a gear ratio calculator the truck should pull 100mph with ease. at 2850rpm with a .71 overdrive, 4.10 rear end and 35" tires 80mph simply doesn't add up. the only thing that could make this realistic is 1- my speedometer is 5mph slow, and 2, bfgs suck and never run true to their size, i bet they measure out 32 or 33", even a true 35" tire that runs big like a mickey thompson still only measures a true 33 and 1/2" tall, MAYBE 34".

 

Well the problems with your figures is that your overdrive ratios are off just a tad. The 47RH has an overdrive ratio of 0.69, but I think most of the trucks in this thread have an NV4500, which carries a lower OD ratio of 0.75, which will make a significant change in your figures.

With a 3.55 rear end, 0.75 5th gear (OD) ratio, and 30 inch tires Im running about 2950 RPM at 99 MPH (what my truck max's out at). With all the rest the same except with 32 inch tires you're looking at about 2770 RPM. You can google search and find the formula for all that

 

well i crawled under my buddys truck and read the tag on the diff and he has 3.54s.

 

Ok well that would make the difference in your race

 

i have 4:10 gears on 33's and with the stock gov springs it would run 85mph and no problem holding it there it wanted to go faster plus gov springs and vaule springs arent alot of cash buy em