37's with 4.10's or 4.30's????

[Ford Cowboy]

Ok, I have a 2000 f350 7.3l srw with 3.73 gears. I wanna do a 6" lift with 37's. I understand that if I keep the 3.73's with the 37's the truck would be sluggish,my mileage would suck, and my rpm's would be through the roof. I get very good mileage now, and I wanna keep it like that. I also would like to keep my rpm's as low as possible. So, which gears would give me the best results (mileage, rpm's, power etc.) 4.10's or 4.30's???? Thanks for any help or suggestion y'all have.

[AnthonyU]

You should be fine with the 4.10's the 4.30's will be to much

[Wyofordpower]

I'd say 4.10's if you dont plan on towing anything. My 97 has 4.10 with stock tires for towing and it doesnt get great mileage but it pulls off the line like a machine, but adding 6 inches of tire is going to knock down acceleration alot.
Using the second calculator on this site gives 4.45 as the new ratio to keep the same rpms, so I'd think that 4.30's would be best overall.
Calulators from www.4Lo.com

[Tj Krawler]

Originally Posted by Ford Cowboy

Ok, I have a 2000 f350 7.3l srw with 3.73 gears. I wanna do a 6" lift with 37's. I understand that if I keep the 3.73's with the 37's the truck would be sluggish,my mileage would suck, and my rpm's would be through the roof. I get very good mileage now, and I wanna keep it like that. I also would like to keep my rpm's as low as possible. So, which gears would give me the best results (mileage, rpm's, power etc.) 4.10's or 4.30's???? Thanks for any help or suggestion y'all have.

I believe 4.30s with 37s will be close to the same RPM as 3.73s with stock size tires. IMO, 4.10s aren't a big enough difference from the 3.73s to be worth the cost.

Personally, I would try it with 3.73s and 37s and see how you like it. If you tow a lot or heavy, I'd go with 4.30s. Maybe even 4.56s if you tow all the time or really heavy.

3.73s with 37s at 70 would be just under 1700 RPM.
4.10s with 37s at 70 would be 1850 RPM
4.30s with 37s at 70 would be just over 1900 RPM
4.56s with 37s at 70 would be 2050 RPM

[Ford Cowboy]

I was kinda leanin towards the 4.10's. Once in a blue moon do I tow with this truck. I mainly run on the highway and want the best mileage I can get with a 37" tire. If theres anybody out there runnin 37's with 4.10's or 4.30's I'd love to know ur mileage and rpms at highway speeds (65-70). Thanks. I currently run like a hair over 2000 rpm at 70 mph with stock 265/75r16's.

[Joel]

Go ahead with the lift and tires. Many people have run 37's with stock gearing. Try it for a bit and if you hate it you can always change after.
No sence spending more money than you have to.

[Jerrybizzle]

Your best highway mileage with 37s will be the 3.73. The place mileage would suffer with 3.73s is city driving due to more mass to get started. On the highway your rpms will be lower with 3.73 resulting in best mileage

[Wyofordpower]

Originally Posted by Joel

Go ahead with the lift and tires. Many people have run 37's with stock gearing. Try it for a bit and if you hate it you can always change after.
No sence spending more money than you have to.

I totally agree, but you are going to want the new gears after you lift it, unless its just a show truck.

[timmyboy76]

i'm with Joel and JerryBizzle, on this one...

[gabegoforth]

Ive got 4.10s with 38s. Ive towed 22k a couple of times and 20k more. I just stay out of overdrive on the hills.