The Stovebolt Site Forums The Shop Area Engine Shop changing rearend gears...how difficult?

I just finished taking off the heads on my 64 c20 w/ 283, having them completely redone and putting it all back together. It actually runs to my surprise. Having never done anything like this before. Now, I would like to change out the ring and pinion gears on my c20. When I go down the road at 65mph the engine seems to be working pretty hard. My guess the rearend is at 4.11 or 4.56...my guess. Given my new experience with the topend, how difficult is it to change out the ring and pinion to something a bit more reasonable, say a 3.56 ratio? Is it more or less difficult than the heads? LMC seems to have the available gear sets, is that all it would take just changing out the two gears?
Any and all opinions welcomed.

-anthony

I don't see where LMC lists a ring and pinion for a 64. You may have to change the whole rear end assembly to get what you want.
Scott

hi scott,
I have the spring edition 1960-66 truck catalogue. On page 84 and 85 it has all the parts for differentials. For c20s and k20 you can buy ratios from 3.54 -4.10 for 199.95, with the 4.56 gears for 249.95.
-anthony

The procedure should be in your shop manual. I'd replace all the bearings and seals while I was in there. You'll need some special tools which you can probably make.

Go to my \'54 GMC page and click on "rear suspension".

The gears in the LMC catalog are for the Dana rears per note "A". Most of the trucks of this series have the 10 bolt Eaton with the round cover. Be sure what you have before you order, and don't depend on LMC having tech support that can help you.

If you have the Eaton HO52 rear and 4.57 gears, you can do a pumpkin swap and get 4.10 gears, if you can find the pumpkin. The HO52/72 was discontinued in 72. Another option is a pumpkin swap from a 14 bolt full floater, but you have to swap the axles due to a spline change. 3.73s are an easy score that way, but you will need to find one with the same axle length.

LMC only lists the gears for 1965 and 66 models. I don't see the 64's,
Scott

Here's a link to "Happy Rear Ends"
http://www.2quicknovas.com/happyrearends.html

It's really a good tutorial on what you need to do in order to set up a rear end when swapping gears or center sections.

It's a considerable amount of work, but it can be done if you take your time and follow the directions.

hey scott,
here's the link:
http://www.lmctruck.com/icatalog/cbe/0085.html
Everyone, thanks for the input. I may give it a try this winter.
-anthony