1963 GMC what rear end?

[neto]

This is really getting interesting. This may actually be a NAPCO rear end. That's why the BOM number was changed.

[Captainfab]

No, it is definitely a Dana rear end. After having seen the pic with the '60' on the casting, I'm thinking you may have one of the rare Dana 60's with the 6 lug axles. I didn't know they existed until I read about it here on the forum several months ago.

I'm thinking you may need to get a set of custom axles to replace that one bad one.

You might try sending a PM to 71Bowties. He has a 6 lug Dana 60, and he might be able to help you find what you need.

Originally Posted by neto

This is really getting interesting. This may actually be a NAPCO rear end. That's why the BOM number was changed.

[neto]

Thank very much. Will pm him.

[neto]

So dumb, I miss counted the splines. It's 30 count. I got the bearings from napa, so the quest continues.

[justcuz]

I would guess it was for a heavy GVW package on the Suburban. The BOM may have been changed for GMC parts matchup since the rear axle is not common.
GM stopped using Napco conversions in 1960, unless it was a 3/4 ton suburban (8 Lug) or panel or 1 ton pickup.
If it was a Napco it would have had HO52 or HO72 front and rear axle housings with the dropout center sections like a 9 inch Ford. Someone posted up a picture of a 1 ton GMC panel truck that was a Napco showing the axles.
What you have is actually more unique than a Napco, not many Dana 60 semi-float rear axles were used in early GM products, especially a Suburban.
The most common modern use of the semi-float Dana 60 today is in light duty F-250's from the 80's.

[neto]

I can't even find the right brake bar for the e brake. "unique=PITA" lol. But I will take the challenge. Having the second drum coming the first one was not deep enough at the axle. The bar is a bendix 303397 but can't find it. I wonder if I can make one? Has anyone make one before?

[justcuz]

See if that bar cross references to an 80's Ford F-250 with the semi-float Dana 60 rear axle. You might get lucky and find that the backing plates and brakes could be the same. Ford used the semi-float Dana 60 from 1980 untill they started using the Sterling rear axle (around 85-86).
In the 60's some F-100's had a Dana 60 semi-float rear axle, probably just as "unique" as your GMC rear end, but may be another source for cross referencing parts.
I don't know what size the brakes are but I am guessing they are smaller than the regular brakes on a full floater Dana 60, otherwise you could just use those parts. I know the hubs and drums would be different but you may be surprised at how much of the stuff from the baking plate out may interchange.