Best Gear Ratio

[bigbluesuburban]

A buddy has a couple sets of gears that I can buy for a 14BFF and D60. I want to know if either of them would be good in my Suburban.

I have an 89, TB350, 3SP Auto, and I will be running 35's this summer. I use this truck as my DD and I also tow with it regularly. In the future I plan to install a few power addon's like a cam, intake, exhaust and if I am really froggy some kind of forced air induction.

With all this in mind... what gear ratio would YOU recommend for this scenario?

 

[Hogback Fabrication]

4.10

 

[bigbluesuburban]

4.10

I think that's what's in the truck now... I will check my axle tag this evening.

 

[randy88k5]

Are you sure it is a 3 speed auto? I thought it would be a 700r4. If you do have overdrive, I would say 4.56... or 4.56 if you are not too concerned about gas milage, I think that would be a little more in the powerband.

 

[55Willy]

yes he has the th400, his burn is a 3/4 ton, the halves got the 700r4.


i'd go 4.56's, Lee

 

[bigbluesuburban]

I was thinking 4.56 also. I can get a used set of gears for the 14BFF in that. I will need to buy the install kit and gears for the front though.

Now I need to find a SRW D60 for the front.

 

[Hogback Fabrication]

I have 4.56's and 37's and feel mine spins too many RPM's to hold anything over 70. Power is definitely not an issue (1/8 throttle maybe) but 3000 RPM is my limit.

35's and an auto with no overdrive would be significantly higher than that. Your TH400 doesn't have a lockup torque converter so that adds to the RPM it would spin on the highway. If you don't plan on going faster than 60 or so than 4.56's might be the right call.