Rear Gear

[bowtieboy93]

I was wondering what axle gears would be ideal for my truck. I have a 350 With what will be around 300 - 350 HP with a TH350 tranny and I am getting a posi carrier from my dads friend. This will not be my daily driver but I hope to drive it alot and I was just wondering what will be the best for it.

[84_4x4]

could always use 4.10 or 3.73 depending on how important gas mileage or takeoff power is to you

[Jondotcom]

If you do any freeway I wouldn't go any higher than 3:73... I'd actually say 3:54 or so it would be good for both quick spurts and freeway cruising.

I'm wondering what where the gear options originally?

[bowtieboy93]

Gas milage doesnt really matter 2 me im gonna have 2 trucks by the time im done i just need to to pass stupid air care (thing we have up her if your vehicle gives off to much of a certain chemical in the exhaust u cant insure it until its fixed. but it looks like it will be done in 2 years cuz so many vehicles are "earth friendly") and freeway prob not to much a couple of times to work. And maybe to the hockey game but thats it.

[bowtieboy93]

The original gears are 3.07:1 which gotta go

[killer71]

depends on what your using it for. If your gonna be on the free way and not pulling anything I would go with a 3.08 (just driving). If your gonna be pulling a load, racing, etc then go with a 4.10. I recently changed from a 3.73 to a 3.08 because I do free way, local driving. I don't pull anything and will never be a hotrodder. Just my .02

[Longhorn Man]

I was gonna recomend a set of 3.07's. I had them in my old 1/2 ton and they were fine. It would launch like a raped ape, and cruise at a semi decently low RPM.

[killer71]

Originally Posted by Longhorn Man

I was gonna recomend a set of 3.07's. I had them in my old 1/2 ton and they were fine. It would launch like a raped ape, and cruise at a semi decently low RPM.

I'm with Longhorn Man!

[msgross]

won't it matter what posi carrier he gets? That could limit you to 3.73 and up or lower than 3.73..

[jay_shy]

Summit racing sales a 3.73 gear set for series 3 and series 4 carriers. I think the 3.73 gear set for the series 3 carrier are thicker if I understand correctly. Has anyone tried the thicker gears, and how did it work out for you.

Jason

[Tx Firefighter]

You fellows can have your 3.73's. I was cruising 80 on the freeway yesterday and enjoying the hell out of my 3.07 gears.

[mnunn454]

I have 3.73's and in hindsight wish I had something [numerically] lower. this 10 MPG stuff ain't much fun.

3.07s with a stall converter in a 3 speed TH350 tranny would take off fine and still cruise reasonably.

If I get the opportunity to install a TH700 with the 30% overdrive, I'll have the best of both worlds, takeoff and cruise.

[1968SWBBigBlock]

3500 RPM, with a 28" tall tire and a 1.00 gear ratio in the tranny would equal
Gear2.59 Speed112mph
Gear 2.73 Speed106mph
Gear 3.08 Speed 94mph
Gear 3.36 Speed 87 mph
Gear 3.55 Speed 82 mph
Gear 3.70 Speed 78 mph
Gear 4.11 Speed 70 mph
Gear 4.56 Speed 64 mph


I hope this helps, I like have a number of miles with big blocks and 3.73 rear ends with no compliants. That said we are almost done with 4.10 gears in the new rear end.

[pat]

I was worried about my 3.07 rear being a little to high, but you guys are making me feel better. Plus its a posi and Ive got a 2500 stall TCI tconverter.

[Longhorn Man]

that converter may end up burning up the tranny.
You'll be slipping on the converter untill you get to 65 MPH, which is at the stall of the converter.
So when ever you will be driving, if you are in 3rd gear and not doin 65, you'll be heating up thetranny REAL good.

[Kager67]

Originally Posted by Longhorn Man

that converter may end up burning up the tranny.
You'll be slipping on the converter untill you get to 65 MPH, which is at the stall of the converter.
So when ever you will be driving, if you are in 3rd gear and not doin 65, you'll be heating up thetranny REAL good.

I agree. I run about 2700 at 65 and don't dare put more than a 2000 stall in mine. With the way my motor is built I should have at least a 3000 stall......oh well.

kage

[Kager67]

As far as your original post, I would go with 3.73's. You say your not worried about mpg, and with not too much highway driving, they would work good. You will be turning a few more R's, but the extra snoot is worth it in my opinion. Another factor is the exhaust. If your running a loud exhaust, it will be just that much louder in the cab with the 3.73's. Just something to think about.

kage

[pat]

Son of a ......

Not trying to jack the thread, but should I get a new converter or new rear end gears, which I kind of wanted..?

[Kager67]

It depends on what your going to use it for. If you have a 'built' motor that you want to do some racing with, its time for new gears. If you do mostly cruzin and have a pretty tame motor, its time for a different converter. The drag racing experts on here know alot more about this than I do, but with 3.07's I'm not sure you should use much more than the stock converter.

kage

[GREASEMONKEY72]

i have 3.07's with a stock rebuilt tranny so its the stock converter and it takes off good for the engine being stock and it cruzes really good and its nice to drive on the freeway and i can haul ass if i want to, so i would recommend the 3.07's but no lower then 3.73's

[69GMCLonghorn]

Overdrive is definitely where it's at, more so than the rear end gear. If you're spending the money on a different rear end, posi, and the right gears, probably decent tires, why not get 4.10 gears and invest in a 700R4?? You get the best of both worlds. A friend of mine swapped a TH350 for a 700 and gained 5 MPG in a 400 HP Nova. It had all the low end the tires could handle and cruised at 110 at just over 3000.

[GREASEMONKEY72]

110 at a little over 3k, sweet

[mnunn454]

Originally Posted by 69GMCLonghorn

Overdrive is definitely where it's at, more so than the rear end gear. If you're spending the money on a different rear end, posi, and the right gears, probably decent tires, why not get 4.10 gears and invest in a 700R4?? You get the best of both worlds. A friend of mine swapped a TH350 for a 700 and gained 5 MPG in a 400 HP Nova. It had all the low end the tires could handle and cruised at 110 at just over 3000.