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?



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.