The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1973 - 1987 Chevrolet & GMC Squarebody Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 05-06-2010, 03:57 PM   #1
Big Cliff
Registered User
 
Join Date: Jul 2009
Location: HEB Texas
Posts: 35
Factory gear ratio's

I have done a search and could not find anything. I have a 1985 swb 2wd 10 bolt that came factory with a 5.0l 305. What did the factory offer for gear ratios? 2.73 or 3.08???????

Last edited by Big Cliff; 05-06-2010 at 03:58 PM.
Big Cliff is offline   Reply With Quote
Old 05-06-2010, 04:07 PM   #2
RandyP
Getting Old; Going Broke
 
RandyP's Avatar
 
Join Date: Apr 2010
Location: Owasso OK
Posts: 2,764
Re: Factory gear ratio's

You should be able to use the RPO codes (in the glove box) and figure out what you have, as long as it has not been changed over the years. I believe most common is 3.42. RPO code is probably a G** one for your year model.

http://www.73-87.com/chevy_ids/rpo-eg.htm#rpo-g , easier way is to just link you. Has been a wonderful link for me decoding some stuff.

Last edited by RandyP; 05-06-2010 at 04:15 PM.
RandyP is offline   Reply With Quote
Old 05-06-2010, 04:45 PM   #3
piecesparts
Parts and more parts
 
piecesparts's Avatar
 
Join Date: Nov 2003
Location: Lebo, Kansas (middle of nowhere
Posts: 6,821
Re: Factory gear ratio's

My guess on which ones was the most common would center around 3.08 gearing. There seems to a lot of those rear ends in the salvage yards.
__________________
Frank
piecesparts is offline   Reply With Quote
Old 05-06-2010, 04:57 PM   #4
baclay9
Registered User
 
Join Date: Apr 2010
Location: Newcastle, OK
Posts: 1,344
Re: Factory gear ratio's

Should the codes on your truck tell you what you have? Only thing is I know the glove box in mine isn't original. Any other way to tell your gearing? Mine has a 12 bolt rear in it.
baclay9 is offline   Reply With Quote
Old 05-06-2010, 05:39 PM   #5
scottsdaleowner75
Account Suspended
 
Join Date: Mar 2010
Location: So. Cal, Inland Empire
Posts: 199
Re: Factory gear ratio's

I have an 86 SWB with originally a 305 in it and it has 3.08's in the rear.
scottsdaleowner75 is offline   Reply With Quote
Old 05-06-2010, 07:42 PM   #6
foamypirate
Registered User
 
foamypirate's Avatar
 
Join Date: Apr 2009
Location: Pflugerville, TX
Posts: 594
Re: Factory gear ratio's

87 LWB, 305 and 3.08s.

It's slow.
foamypirate is offline   Reply With Quote
Old 05-06-2010, 10:24 PM   #7
GMC Guy
Registered User
 
GMC Guy's Avatar
 
Join Date: May 2009
Location: Sparks, NV
Posts: 913
Re: Factory gear ratio's

79 gmc factory 350.... 3.08's :[
__________________
Greg
1974 GMC
1/2 Ton SWB Fleetside
L33 5.3/4l65e

.................__
............._____l __\__
..............l_(O)_ l___(O)]
GMC Guy is offline   Reply With Quote
Old 05-07-2010, 09:46 AM   #8
Big Cliff
Registered User
 
Join Date: Jul 2009
Location: HEB Texas
Posts: 35
Re: Factory gear ratio's

Thanks guys, it has the 3.08's. I ordered a set of 3.42's should help it.
Big Cliff is offline   Reply With Quote
Old 05-07-2010, 11:25 AM   #9
LONGHAIR
just can't cover up my redneck
 
Join Date: May 2004
Location: Columbus OH
Posts: 11,414
Re: Factory gear ratio's

What transmission? tire size? That's a pretty expensive swap to not nail it exactly...
__________________
You can review the site's rules here.



Quote:
Originally Posted by Longhorn Man View Post
As for reading directions...
The directions are nothing but another man's opinion.
Learn from the mistakes of others, you won't live long enough to make them all yourself...

Bad planning on your part does not necessarily constitute an instant emergency on my part....

The great thing about being a pessimist is that you are either pleasantly surprised or right.
LONGHAIR is offline   Reply With Quote
Old 05-07-2010, 12:23 PM   #10
Jonboy
Slots go on anything!
 
Join Date: May 2003
Location: Richardson, TX
Posts: 5,957
Re: Factory gear ratio's

a 700R4 will be spot on after that. The low 1st gear is better, too.
__________________
1974 Jimmy- 5.3/4L80e/NP241
Jonboy is offline   Reply With Quote
Old 05-07-2010, 12:35 PM   #11
GmtGmt
Conversion Truck Addicted
 
GmtGmt's Avatar
 
Join Date: Sep 2009
Location: Denmark, Europe
Posts: 1,551
Re: Factory gear ratio's

What would a C30 6.2 4 speed have 4.10?
dont have RPO cods or the tag on the rear end
__________________
Thomas

Quote:
Tonight mine pulled a few cars out of snowbanks, and is sitting in my driveway, icicles on the grille, wheels just white cakes of snow, buried up to the lug nuts in powder, straps and chains wrapped around the bumpers, the outline of the wipers clear in 4 inches of snow on the windshield... A tired warrior of the 1980s in a world of low profile tires, front wheel drive, and plastic bumpers, where people stay in their houses until snowplows move the offending substance from their paths, too helpless to travel without AAA and chains and salt, clearing their windows with longhandled brushes while gently stepping around in the snow trying to stay nice and dry.

Last edited by GmtGmt; 05-07-2010 at 12:35 PM.
GmtGmt is offline   Reply With Quote
Reply

Bookmarks


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 04:52 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com