In search of 3:42 O-type gears, before I buy the Richmond set

 

Richmond set is for 3.08 and 3.23 carrier. OEM 3.42 gear is for different carrier.

 

Is this not correct

https://m.summitracing.com/search?ke...mond%204900491

 

Correct for what? Yes, they are correct for installation on a factory 3.08-3.23 carrier, but not correct for a factory 3.42 carrier.

Here's some O-Type info that Brian Trick posted many years ago. This shows there are essentially three series of carriers and gears are made specifically to fit a particular series.

O-Type 12 Bolt

Here is a list of the posi units & what gears they will fit:
#673 = 2.56 & 2.78 ratios, 28 spline
#671 = 3.08 & 3.23 ratios, 28 spline
#588 = 3.42 & anything numerically higher, 28 spline
#672 = 3.42 & anything numerically higher, 31 spline
***The 31 spline axles were offered in late 67-68 OAI cars only.

 

Ok, I have the 673 carrier and received the same information from Brian Trick. I didn't realize 3:42 wasn't a factory gear.
I appreciate the responses and help

 

What are you talking about? Of course 3.42 is a factory gear set.


Read the above posts again.


Your 673 carrier will not work with factory 3.42s or with the Richmond gears either.

 

I believe those summit gears will only work with a 671 carrier? Not totally sure but Brian or Monzaz will tell you for certain.

 

heres your summit gear description;
Richmond Gear 49-0049-1 - Richmond Gear Ring and Pinion Sets
Click here for more information about Richmond Gear 49-0049-1 - Richmond Gear Ring and Pinion Sets
$30.00 Summit Bucks
Free Shipping
Gear, Ring and Pinion, 3.42:1 Ratio, GM, 8.5 in., O Axle, 10-Bolt, 3 Series, Set

says right there in last line -- 3 series --- that specifically means a 588 or 672 carrier!

 

Hoped we saved you some money buy buying something you cant use!!

 

I think that is incorrect. The Richmond gears are made to fit the 671 carrier. I have no idea what "3 series" means for the O-Type as there are 3.xx gears for both the 671 and 588/672 carriers.

 

Did Brian mention that you can get a ring gear spacer and use the Richmond gears on your 673 carrier? There were several posts about this in the past week and apparently monzaz is the source for these.

https://classicoldsmobile.com/forums...ar-spacer.html

https://classicoldsmobile.com/forums...swap-help.html

 

I think "3 Series" denotes the "3's only" ratios of the 671 carrier.

 

I have the spacer

 

My Bad.. You are correct. However he CAN use the spacer with his 673.

 

Well, if we call the 673 carrier (for 2.56-278 gears) the "2 series" then the next logical step is the 3.08-3.23 are the "3 series" which leaves the 3.42/3.91/4.33/4.66 as the "4 series".

So much easier to just say which factory gear range it covers and leave the ambiguous "series" nomenclature out of the conversation.