61 ho 32 to 64 12 bolt ?

[bosephus]

Is the 64 12 bolt rear diff a " bolt in" replacement for a 61 ho 32. Panhardbar mount looks good but I was wondering if the trailing arm mounts were the same .thanks!

[Dillon Rock]

Do you have an Eaton Ho 32?

[Captainfab]

You will have to move the trailing arm mounts on the 12 bolts since the '60-'62 trailing arms are farther apart. The '61 panhard bar should work with the '64 12 bolt

[bosephus]

Thanks captain !

[LostMy65]

How about the length of the driveline?
Can I remove my 62 Ho32 and mount a
65 12-bolt without modifying my driveshaft?

[Captainfab]

Having not done that swap, I do not know for sure. I can measure a 12 bolt and a HO32 at the shop tomorrow and let you know.

Originally Posted by LostMy65

How about the length of the driveline?
Can I remove my 62 Ho32 and mount a
65 12-bolt without modifying my driveshaft?

[bosephus]

I still haven't swapped mine out so I can't answer your question,but that's an angle I didn't look at

[LostMy65]

Originally Posted by bosephus

I still haven't swapped mine out so I can't answer your question,but that's an angle I didn't look at

You've had over a year! :-D

[Captainfab]

Okay here's what I came up with. These measurements are not ultra precise, but are fairly close. With the truck 12 bolt, the center of the axle tube to the center of the U-joint on the pinion yoke measures 11-5/8". The Eaton HO32 measures 12-1/4" from the center of the axle tube to the center of the U-joint on the pinion yoke. So the driveshaft will technically be 5/8" too short if you swap in a truck 12 bolt, but with that small amount it may be fine. It just depends on your particular driveshaft and trans.

[LostMy65]

Thanks
That helps a lot.
I want to go to a th350 from my sm420.
I didn't want to size my driveline to the ho32 and then have to do again when I went to the 12-bolt.

[LostMy65]

Now that I have a 12-bolt that I can measure, I just did some measurements of my own.
I got pretty much the same measurements as Captain.
Also, it looks like I won't have to remove the existing axle perches. The trailing arms on the 62 are far enough apart where I should be able to mount the new perches right next to the existing ones.

[OldChevy61]

On my 62, the pan hard bracket had to move over in order to use the 62 bar. Or you could get and adjustable. I was paying a welder anyways so just moved mine. Not sure about the perches as we removed the 64 ones and put a set of captains new ones on. Seems like the old ones had to come off to get the same measurement as the ho32.

[61ChevyPanel]

It was a while ago when I put a 12 bolt from a '64 in my '61 Panel. It was the same width. Did have to move & re-weld the brackets but other than that, it was fairly simple. Can't remember if I changed the pan hard. Current piece is non-adjustable about 33" long. Can't remember if I had to change U joints.

[LostMy65]

Originally Posted by 61ChevyPanel

It was a while ago when I put a 12 bolt from a '64 in my '61 Panel. It was the same width. Did have to move & re-weld the brackets but other than that, it was fairly simple. Can't remember if I changed the pan hard. Current piece is non-adjustable about 33" long. Can't remember if I had to change U joints.

.
Do you remember if you had to resize your driveline?
I just dbl checked my 65 12-bolt and my 62 Eaton Ho32, and the 65 12-Bolt looks to be at the very most, 1 inch shorter than the 62 Ho32.

[61ChevyPanel]

It was 20 years ago but I really don't think I had to make any changes to the driveshaft. To be honest, I don't know if I did check to see if the lengths of the two rears were different. I used a straight panhard bar at 33 5/8". Haven't had any rear end issues since the swap.

[LostMy65]

Thanks
It's neat you've had your truck so long.

[LostMy65]

Anyone know the Torque requirements for the axle mounting U-Bolts?

[verdell]

Just ran across this thread and wanted to share what I have. I swapped out the 1960 HO32 for a 1965 12 bolt and always thought it may have been a tad too short. It never gave me any issues so ran it for years. I recently found out I have an unpleasant vibration just over 90 mph. Checked pinion angles, tranny mounts, axles, every thing but according to a drive train specialist in this area, my driveshaft is short. This seems to be the cause of the vibration. Just an FYI...