84 k10 4x4....3.08 gears?

[dman1982]

i belive my truck has 3.08 gears...is anyone else running these gears....i got 35 inch tires on my truck and this thing is really really slow...i know a big truck wont be a speed demon but a chevette would kill this thing!!!!

[48cj2a]

I ran up to 40's on a Blazer I had with just 3.08s. It was no power house and tough on gas but I never had any real problems.

Watch the message boards and craigs list. Peolple are always upgrading axles and you could pickup a complete set of 3.73 or 4.10 axles fairly reasonable already to swap if money is an issue.

Another good source is x-military M1008 trucks which have Dana 60 and 14 Bolt rear with a detroit locker and 4.56 gears but you would have to switch to 8 lug rims and 16 or 16.5 tires.

[dman1982]

if i switch to 3.73 or 4.10's will it help my gas mileage at all? right now i have a turbo 350 and i was thinking of regearing it and going to a 700r4, thats what it originally had in it...not anytime soon but after i put a new motor in it, that is what im looking to do next

[Plunkett]

I've got a 86 chevy silverado with a 700r4 tranny, 35" tires, and 4.56 gears. I'd def. ditch the 3.08 gears for something lower. If you keep the turbo 350 tranny, I would go with a 4.10 but if you swap to a 700r4, I'd run a 4.56 gear like I have. That's just my opinion.

[dman1982]

did you switch out the gears? and did you get better mileage? im kinda looking to get better mileage and a little better performance....kinda like a happy medium...right now my truck doesnt do too bad of mileage but always looking to do better....but its soooooooooo slow...not sure if its the gears or tired motor

[Plunkett]

Ya, I swapped the gears out when I lifted my truck. My speedometer is off, so I'm not exactly sure on my fuel mileage. Before the lift, I had 3.08 gears with 31's and I seem to use the same amount of gas each week with the new gears and tires. I've currently got a 305 in the truck and I like my gear selection. Like I said in my other post, you really need to decide which transmission you want to run before you decide to regear it.

[dman1982]

i think im going to eventually go with the 700....i really want overdrive...just keeping my options open.

[scottsdaleowner75]

I have an 86' K10 SWB and did the same thing as you. I lifted it 4" and installed 35x12.5x15's and regeared with 4.10's. My truck has the 700R4 originally too and can tell you go at least 4.56's. If you keep the th350 or go a turbo 400 then i'd go 4.10's. That is my only regret. When i get it on the freeway i feel like it is barely idling am I"m doing 60mph.

[dman1982]

hmmm...sounds like thats what im going to do....what kinda mileage were you getting?

[scottsdaleowner75]

I have a GM 290HP crate engine with all the factory stuff on it and some C.A.R.B edelbrock headers with a quadrajet. I get around 14mpg if i keep it at 60mph. I do have lockers front and rear with those 4.10's too

[Plunkett]

Originally Posted by scottsdaleowner75

I have a GM 290HP crate engine with all the factory stuff on it and some C.A.R.B edelbrock headers with a quadrajet. I get around 14mpg if i keep it at 60mph. I do have lockers front and rear with those 4.10's too

Not to hijack the thread, but how do you like t he gm 290hp motor? I'm looking into options of swapping out my tired 305 for a new motor. I'm getting 10-11 mpg now. I'd like to get a little better fuel mileage.

[48cj2a]

There is an ad on the classifieds right now with 4.10s but 3/4ton ready to bolt on.

[scottsdaleowner75]

I like it. It has good power and runs smooth. When i ditched the Quadrajet that had a dual capacity accelerator pump for a quadrajet without it it ran MUCH better. All i need now is a new exhaust from headers back to be complete.