Rear gear ratios - how low can I go? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**ScottH** · 03-22-2004, 11:57 PM

I have a series 3 posi and was wondering what my options were should I decide to change ratios.

Any info is appreciated.

Thanks.

walker · 03-23-2004, 12:06 AM

With a series three you can go as low as 3.73, I believe. After that you need a series four.

bigjimzlll · 03-23-2004, 12:53 AM

you can go to 4.56 with thicker gears made for a 3 series

**kwmech** · 03-23-2004, 01:37 AM

With the correct case I believe you can go to a 5.38 ratio in a 12 bolt

**smitty62** · 03-23-2004, 01:49 AM

Series 3---2:76 to 3:42

cdowns · 03-23-2004, 01:53 AM

Quote:

Originally posted by smitty62
Series 3---2:76 to 3:42

that's only for stock gears ,richmond gear has them like was stated to 4:56 for the series 3 carrier and i'm sure there are other companys offering them as well

Cat Fuzz · 03-23-2004, 02:38 AM

Quote:

Originally posted by kwmech
With the correct case I believe you can go to a 5.38 ratio in a 12 bolt

**smitty62** · 03-23-2004, 11:28 AM

Quote:

Originally posted by cdowns

that's only for stock gears ,richmond gear has them like was stated to 4:56 for the series 3 carrier and i'm sure there are other companys offering them as well

Believe you have to use spacers, which is not recommended by Randy's R&P--I'd stick with stock configuration.

cdowns · 03-23-2004, 11:31 AM

Quote:

Originally posted by smitty62

Believe you have to use spacers, which is not recommended by Randy's R&P--I'd stick with stock configuration.

NO SPACERS REQUIRED THEY MAKE THE GEARS THICKER

Vince M · 03-23-2004, 06:56 PM

There are spacers available that will allow a 4 series gear to fit in the 3 series carrier and as stated you can also purchase the thicker gears for the three series. Pretty much the same idea just a different approach.

2low72 · 03-23-2004, 08:36 PM

is there a way to check what the gear ratio is in the rear end without pulling the diff cover?

03-22-2004, 11:57 PM	#1
ScottH Senior Member Join Date: Sep 2002 Location: Hampstead, NC Posts: 8,190	Rear gear ratios - how low can I go? I have a series 3 posi and was wondering what my options were should I decide to change ratios. Any info is appreciated. Thanks.

03-23-2004, 12:06 AM	#2
walker Registered User Join Date: Jul 2003 Location: north of Phx AZ about 30 miles Posts: 698	With a series three you can go as low as 3.73, I believe. After that you need a series four. __________________ Andy,Phx AZ '67 C-10 (Ahhh, done at last. Well there is that disk front end I want to put in and...) "23 C-Cab-sold '48 Ford 8N tractor(still working) '67 Scout(Now on the road) '70 MG B.-sold

03-23-2004, 12:53 AM	#3
bigjimzlll Senior Member Join Date: Dec 2001 Location: Redding,CA...USA Posts: 4,736	you can go to 4.56 with thicker gears made for a 3 series __________________ It's called "drag racing" if they called it "tic..tic..WHAM!..BANG! F*&K!!!", they'd have to keep the magazines under the counter with the other men's publications click the clicky to join the site.... http://67-72chevytrucks.com/vboard/payments.php 67 lwb..first hotrod in 25 years..540 best ET is 9.45 @ 141.44 Anderson,CA

03-23-2004, 01:49 AM	#5
smitty62 Registered User Join Date: May 2002 Location: North Carolina Posts: 1,234	Series 3---2:76 to 3:42 __________________ Stepsides look like real trucks! Smitty

03-23-2004, 06:56 PM	#10
Vince M Senior Member Join Date: Apr 2000 Location: Orlando, FL Posts: 1,076	There are spacers available that will allow a 4 series gear to fit in the 3 series carrier and as stated you can also purchase the thicker gears for the three series. Pretty much the same idea just a different approach. __________________ ............................................................ 68 Chevy CST SWB w/LS1, carb & 700r4. Golden Anniversary clone with a few improvements.

03-23-2004, 01:37 AM	#4
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,628	With the correct case I believe you can go to a 5.38 ratio in a 12 bolt

03-23-2004, 08:36 PM	#11
2low72 Registered User Join Date: Mar 2004 Location: Cheyenne, Wy Posts: 555	is there a way to check what the gear ratio is in the rear end without pulling the diff cover?

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