What gears do I need?

[BearKing]

According to my chart, 4.11 gears with 35” tires will have your engine turning 2565 rpm. 33” will be 2720 rpm and 31” tires will be 2896 rpm. Now 4.56 with 35” tires will be 2845 rpm. With 33” tires it will turn 3018 rpm. And with 31” tires, it will turn 3213. Just food for thought. I have the formula for figuring out the rpm/ratio/tire size. If you need more info, please ask and it’s yours. Good Luck young man.

 

[dvdswan]

Depending on what your usage for the truck is going to be, having a locking device at least in the rear if not both axles would be a great upgrade. If towing, you will want one in the rear axle.

 

[Strick]

I would stay with the 4.10 ratio with the 35's. Using the thick R&P will keep from replacing the carrier as well.

Strickland

 

[HEG77k10]

According to my chart, 4.11 gears with 35” tires will have your engine turning 2565 rpm. 33” will be 2720 rpm and 31” tires will be 2896 rpm. Now 4.56 with 35” tires will be 2845 rpm. With 33” tires it will turn 3018 rpm. And with 31” tires, it will turn 3213. Just food for thought. I have the formula for figuring out the rpm/ratio/tire size. If you need more info, please ask and it’s yours. Good Luck young man.

Is that going 70miles an hour in third gear or?

 

[HEG77k10]

Depending on what your usage for the truck is going to be, having a locking device at least in the rear if not both axles would be a great upgrade. If towing, you will want one in the rear axle.

What kind of locker do you recommend?

 

[WebMonkey]

my '85 k20 super double xtra duty has 3.73 and turns 35s and 31s pretty good.
of course my commute to church only gets up to 55mph.
(1969 350sbc, sm465, q-jet)

if i had to re gear something else, i'd probably go with 3.73.
where i live/where i drive, it's a good compromise for an old 350 truck.

good luck

You must be registered for see images attach

 

[Vbb199]

What kind of locker do you recommend?

That's an entire sub post in and of itself.

This forum is plum full of opinions regarding lockers.
Some are bitter and very one sided because they didn't like the drivability of an offroad type locker on the road, some have a preference in this or that because it's lasted them "x" years. Etc etc etc.


The most common one is a Eaton trutrac.

Everyone likes those for on road usage.

I have a preference for Yukon lockers because the only time I got tires spinning is off the road in my utilitarian type vehicles. Like if I'm towing with my suburban and the back tire slips, it locks in immediately and I usually can get thru the muck. My offroad machine has Yukon lockers.

I own a hotrod myself with a significant amount of power, and it's likely I'll put a trutrac in it when the time comes seeing as it'll never be offroad lol

 

[dvdswan]

What kind of locker do you recommend?

Pretty much what @Vbb199 said above. I've had several types of locking devices and can't complain about any of them. Each has its own pros/cons. Currently I have a selectable locker (ARB) in my play toy and love it. I had a lock-rite in the truck before which I had no worries about the clunks or noises on the street. Just do a little reading on them all and decide which is best for you usage. Look at the maintenance schedule for each as well.

 

[Bextreme04]

I've got a yukon Grizzly locker and 4.10's turning 35's. If you aren't hauling anything heavy or towing regularly with your truck, you should probably stick with 3.73's. 4.10's will turn 60-65, but it's wound up pretty well at that point. If you want to daily it on the freeway at 65-70, you definitely dont want 4.10's or higher unless you plan on adding an OD at some point. Since you are a half ton with a 12 bolt, I'd recommend just getting a yukon duragrip and matching 3.73's if you can afford it. It will have good manners on the road and will still help a lot with traction.

https://www.jegs.com/i/JEGS+Perform...RpbvD6ulNMbXq5Nr3yiDTWkaoiiLkbU8aAgEgEALw_wcB

 

[CalSgt]

Go find a shop that sets up gears as part of their regular everyday business like a driveline and gear service shop. Get their advice on ratio and weather or not a new carrier is needed. If you're going to pay a shop to install more often than not they can get you a better deal on the R&P than you can get on your own.

Setting up new gears is more complex and expensive than most would expect, it requires specialized tools and often times a good selection of pinion and carrier shims.

 

[Bextreme04]

Go find a shop that sets up gears as part of their regular everyday business like a driveline and gear service shop. Get their advice on ratio and weather or not a new carrier is needed. If you're going to pay a shop to install more often than not they can get you a better deal on the R&P than you can get on your own.

Setting up new gears is more complex and expensive than most would expect, it requires specialized tools and often times a good selection of pinion and carrier shims.

Very true.

If you want it done right, once, for the least amount of hassle... plan on paying a shop that knows what they are doing to do it right. It takes several hours and some special tools to do it right. For parts and labor, expect to be in the $1K range, give or take a few hundred depending on location. I paid about $500 in parts for both front and rear ring/pinion and rebuild kits when I did my 2011 Suburban and it took me a day for each axle. But I also have most of the tools and still needed to go to a specialty shop to have the carrier bearings pulled.

You can save the money for labor by doing it yourself if you have access to a shop and tools, but you always run the risk of making a mistake and wrecking the new parts you just put in. Also plan on it taking you 2-4x longer than it would take a pro to do it. So you might have your truck down for an entire weekend or more just to do the rear axle. Then you need to do the same thing for the front.

 

[78C10BigTen]

According to my chart, 4.11 gears with 35” tires will have your engine turning 2565 rpm. 33” will be 2720 rpm and 31” tires will be 2896 rpm. Now 4.56 with 35” tires will be 2845 rpm. With 33” tires it will turn 3018 rpm. And with 31” tires, it will turn 3213. Just food for thought. I have the formula for figuring out the rpm/ratio/tire size. If you need more info, please ask and it’s yours. Good Luck young man.

That is helpful info!

 

[78C10BigTen]

Pretty much what @Vbb199 said above. I've had several types of locking devices and can't complain about any of them. Each has its own pros/cons. Currently I have a selectable locker (ARB) in my play toy and love it. I had a lock-rite in the truck before which I had no worries about the clunks or noises on the street. Just do a little reading on them all and decide which is best for you usage. Look at the maintenance schedule for each as well.

Im actually pretty sold on a lockrite for my daily s10. Just havent pulled the trigger yet.

 

[78C10BigTen]

Setting up new gears is more complex and expensive than most would expect, it requires specialized tools and often times a good selection of pinion and carrier shims.

This is why ive always swapped rears instead of "rebuilding" them! Only time i put a posi unit in my 78 it blew apart..... lol

 

[82sbshortbed]

Spicer Engine RPM Calculator

Measure your engine’s RPM based on the ring gear and pinion gear ratio, speed, and tire height, with the Spicer Engine RPM Calculator.

spicerparts.com

2.73.1965rpm..3.08.2217rpm...3.23.2325rpm..3.41.2455rpm..3.73.2685rmp..these are measured at 60mph with a 28in tire.

I've got a 3.73 in mine right now. So if I can't get a 700r4 here pretty soon I'm gonna switch the ring and pinion gears to a 3.08 until I can get the transmission because 2700 at 60 with a bbc sucks. Lol