[62131]

I have located two different rear ends 3.08 and a 3.73 which would give the best performance?

[madmike3435]

the 3.08 will give you excellent cruising, gas mileage due to lower RPM , but will not much in the way of off the line performance but that too depends on camshaft, intake, tire height.  Bigger the tires height wise, more it cuts the gears.

Also depends on powerglide, TH 350, or a 700-R4.

3.73 will tend to buzz the rpm's to 3000 at 70 mph with NO overdrive.

If you know the rear gears in your late model ride with 700R4, slip it into 3rd gear at 1---1 and see what the tack is telling you.

My 2003 S10 v6 with 4.3 and 3.42 gears, 700R4, 60 MPH drop it into 3rd and get 2800-3000 rpm, shift into overdrive at .70 and voila..........2200 rpm


mike     

[ghost28]

I got 373 gears in the roadsrter and at 70 iit's about 2200 rpm in 5th gear. but in 1st gear it's awhole lot of fun.

[62131]

With staying with the S10 4x4 95 thru 97 rear ends available in the 59" wms to wms there's just a few ratios to choose from, it seems the3.08 is the most common. I did find two 3.73's today. Having a stock 350 and th350c with plans on using the lock up convertor while at highway speeds and  the 28" tall tires, I'm thinking the 3.73 is the gear to use.   
What's your opinion?

[sammons]

Well...I'm stuck with 3.08s right now. Have TH350 w/o lock up, 26" tire, I'm betting my 301 ain't going to be a power house off the start. If I had it going I could give more info.  I'll prob build my 350 for lower end power and call it good.

My '69 Vette had 3:73 gears (350/4spd/25" tire) and pulled hard, loved it. Gas mileage wasn't great but not bad at 17mpg @65. I found a 3:55 gear and liked it better, gas mileage came up to 20, just not as quick.

[Rattiac]

I'd probably go with the 3.73's. I would rather have something a bit deeper than a taller gear than be disappointed with a lack of power on take off.
A buddy I cruise with ,  will swap another pair of wheels w/taller tires on long distance trips.

He has a 50 Chevy with a 4.3ltr th350, 3.73 rear.
One day we're gonna race as soon as I get rid of the wood inside.

[TFoch]

If it were me I'd go with the 3:73's.  I don't spend much time on the highway at 75 mph.  I spend more time accelerating from stop lights and cruising the back roads.  The 3:73'swould fit my driving style better than the 3:08's.  Just my humble opinion.
Tom

[EDNY]

With staying with the S10 4x4 95 thru 97 rear ends available in the 59" wms to wms there's just a few ratios to choose from, it seems the3.08 is the most common. I did find two 3.73's today. Having a stock 350 and th350c with plans on using the lock up convertor while at highway speeds and  the 28" tall tires, I'm thinking the 3.73 is the gear to use.   
What's your opinion?

The Blazer has the 59" WMS unit - the S10 truck has either the 54.5" or 63" (ZR2). The 95-97 Blazer axle has drum brakes for sure...but some later units might have drums...but most are disc after 97. Important to note is that if you have factory width leafs springs...the calipers on the disc units won't mount because they contact the leaf springs. I found out the hard way and had to install a drum axle. If you have a 4 link...you can mount either.

I'm sure you know to look in the glove compartment for the RPO codes for gear ratio and posi unit identification.

http://www.sierragear.com/gm-rpo-axle-ratio-identification-codes-3/

[62131]

I see there's a 3.42 out there this might be the gear to find and use?? 

[TFoch]

I see there's a 3.42 out there this might be the gear to find and use??

That's what I have in mine.  Very happy with it.
Tom

[madmike3435]

its the stock rear gear in my 2003 chevy S-10 extreme.

235 x 65 x 16 tires.  At 60 mph in 3rd gear 2800--3000 rpm, slip it ( 700R4 ) into overdrive at .70 and rpm drops to 2200

mike         

[62131]

I found a 3.42 today out of a 98 blazer 4x4  with drum brakes, one more junk yard to check hoping to find a 3.42 with g80 option  found several 3.73's with g80 option today getting closer. I'm not looking for a tire burner more of a cruiser.

[62131]

Well now I'm really undecided on what gear to use. Please help me with a decision

[FATnLOW]

My dilemma is  the 3:42  gears  and   Th 350 transmission......was offered a  700r4  for  cheap...guess i'm going that route..gotta change out transmission mount and length of drive shaft....  what  your opinion?? ...

[62131]

Well I'm being told the 3.42 gear is the perfect gear for the the TH350 and the 3.73 will work fine to just will turn  couple hundred rpm,s higher on highway speeds.  I have already had my transmission rebuilt along with a new drive shaft made. I would like to know how much difference in fuel mileage would it really make between the two