65 C20 Gear Ratio

[65ChevyUtah]

I have a 65 c-20 with an Eaton Ho 52 Rear End with a ration of 4.56. I am thinking of changing to a corp 14 bolt with a 4.11 ratio. Is this worth it for the lower RPMS ? I am running a 327 with a Th400. I am going to get new tires so I can go taller if needed.

Does any know if I will need to change my driveline if I swap?

Thanks for all your help.

[Imperial Kustom]

It will lower the RPM only a by a few hundred. It is definitely more than worth the swap however, because that old Eaton is junk when it comes to parts availability. The picken's are really slim for that rear, but the 14 bolt offers a wide array of parts availability and is much stronger too.

[Fred T]

If you're going to swap go with better gears than the 4.11. 3.73 is real common in the 14 bolt. I saw some once marked 3.42, which would be even better for a driver. Go to www.ringpinion.com for a calculator.

[Captainfab]

I agree, go with a 3.73 if you can find one. But if you can't then go with the 4.10, and then you could always switch the gears later if you want. Like Imperial said, there's lots of parts available for the 14 bolt

[65ChevyUtah]

Thanks for all the advice. The reason I was going to go with the 4.11 was becuase I already have it. It came with a parts trucks I bought. How hard is it to change out the gears ? I am thinking If its not to hard or complex I can get the gears at a wrecking yard and save some $. Thanks.

[Captainfab]

SWitching gears isn't what I would call hard, but you just need to know what needs to be done, have the proper tools and take your time. So it probably depends on your general automotive experience and if you feel you're up for the challenge. You can get a video on how to do it that may help.

[64c20crewcab]

I bought a 14 bolt last year w/t 3.73 r&p to do the swap from the H052. I did not have the $ to do the work so I have it sitting in the garage. Last week justcuz spotted an eaton w/t the 4.10's. I grabbed that H072 3rd member and we installed it last weekend. Makes a huge difference and will be even better once the 700r4 is installed by this summer. Btw I do have disc brakes (14 bolt brackets w/t calipers and prem 88 Blzr front rotors) on the H052 and am hunting for a locker for it.

[factorystock]

Where is the aftermarket on this? I am sure everyone who owns a 1947 through 1972 3/4 ton would love to have a 3.50-3.70 gear set for a truck that is no longer used for work. The Eaton 3/4 ton is similiar to the Ford 9" rear end and can be dropped in and out in 1 hour or 2. The Eaton pumpkin with 4.11 was the highest ratio available and will be the easiest to install without any modifications(more common to find in the 67-72 era trucks).

[Fred T]

There was a guy cutting new gears, Art Houser. Unfortunately, he died in a car wreck a couple of years back.

The reason no one picked up the product was machining cost. With low production rates, the gears were just short of $500.

That was just the bare gears. Unless you have the dial indicators needed to set the gears, there was more cost. And then the bearings added more.

Swapping the differential is a lower cost option, especially if you can weld your own spring perches. And you get more braking surface. You can go with the 14 bolt, but I don't like the angular look. There is also a 12 bolt, 1972-??, with 3.52 gears. And there are a few 4.10 pumpkins out there for the 10 bolt, which is the easiest way to go.

A pumpkin swap is fairly easy. Unbolt the axles from the hub and pull them out a few inches. Disconnect the driveshaft and unbolt the pumpkin on the front of the differential housing. The entire pumpkin pulls out the front, but it's not light. Best done by two people. Put the new pumpkin in place with a new gasket, attach the driveshaft and put the axles back in place. Bolt it all together and fill with gear lube.

[Captainfab]

Don't forget about the Dana 60's for the C20's. I don't think there were many used in the '67-'72 years.....I got lucky and found one with 3.54 gears....'71 C20 with an auto. I don't recall how the widths compare, but f**d used Dana 60's quite a bit in their 3/4 tons.

[65ChevyUtah]

Thanks for all the advice everyone. I am going to swap it out for sure.

Has any one reused the perches ?

I just have a hard time spending $150 for perches..

[Captainfab]

Originally Posted by 65ChevyUtah

Thanks for all the advice everyone. I am going to swap it out for sure.

Has any one reused the perches ?

I just have a hard time spending $150 for perches..

Whoa where you been shopping? Seems like I've seen them somewhere that were reasonably priced....I'll see if I can remember where. I would just carefully cut the old ones off and reuse them if you have a way to do it.

[65ChevyUtah]

well at classicparts.com its $129 plus shipping. Any help on finding where they are reasonable. would be great. Thanks.

[64c20crewcab]

Hey 65, Ya may wanna take a look at this build for ideas for the spring perch swap to a 14bolt:
http://67-72chevytrucks.com/vboard/s...=252364&page=7

Seem simple enough if carefull with the removal off the Eaton.
Good Luck.

[65ChevyUtah]

Thanks everyone for all the Help. I checked out that post and it gave me some good ideas.

[65ChevyUtah]

UPDATE:

I was able to remove the old perches useing a grinder and cut off wheel. Thanks for all the help ! I'll post some pictures soon.