1962 Differential

[K98AL]

New guy here - got a '62 LWB with 4 speed tranny, original posi rear end, and a 235. I'd like to keep the tranny, and change ratio on rear end, but the gear kits I've seen will only get down to 3:38 I believe.

With the granny tranny, I should be able to go to a 3 or 3:08 ratio without burning out the clutch.....so...

What's the best way to get that ratio? Are other gear kits available that I'm unaware of? Swapping entire rearend? How difficult is that?

BTW - I do plan on putting a lot of highway miles on.

Any help/ideas are GREATLY appreciated.

[1963c-10]

Welcome to the forum, always glad to have new faces and pics around. Im sure some guys will pipe in to help you out.

[Clyde65]

If your going from a 4.11 to a 3.38, that is a jump that should make a big difference I would think, also what size tires are you running? I am no expert at all, just regurgitating what I have read here.

Sorry bud, Welcome from Texas!

[Captainfab]

To get a better selection of gear ratios, you are going to have to change that HO32 for a truck 12 bolt. The 12 bolt was first offered in the '63 model year. Any 2wd 12 bolt thru early '70 will be the same width as well as 6 lug. However, you will have to do some cutting and welding. The trailing arm mounts will need to be moved, and depending on the rear end you get, a panhard bar mount may need to be welded to the new rear end. The '63 and '64 12 bolts have the same panhard bar mount as your HO32.

[K98AL]

Running plain 'ol 15" tires. Are the posi rearends in all the '62s 4:11? I haven't had the cover off yet, so I'll have to check that out. Thanks for the info, sounds like I have a project...

[Wrenchbender Ret]

With a 235 I think 3.38 will be all you can pull. If you go to a 3.08 you are going to bog down on long hills & with that Granny type 4 speed, downshifting would be awkward.

[blackedoutharley]

When we say "tire size" we mean the actual size or the actual diameter. Tire size can and does change effective gear ratio.

Going from 4:11's to 3.38's is like night and day and with a tall enough tire you may find you don't need 3:08's. or to go through the hassle of changing the entire rearend to get them.

[markeb01]

Although they don’t exactly grow on trees, another direct swap would be a Dana 44 from a 60-62 GMC. The ratios range from 3.08 to at least 4.11. There are two carriers. One covers from 3.08 to around 3.70. The other is required for the lower gears (higher numerically).

I agree with the comments above however. Going all the way to 3.08 with a six may be too tall a gear and cause the truck to run at an rpm that is below the torque curve of the engine.

And welcome to the forum!

[Captainfab]

It has been my experience with the HO32's that the most common gear is the 3.90.