The Stovebolt Site Forums The Shop Area Engine Shop Rearend ID?????

I posted this on a couple other sites... did a search... nothing. Anyone????????

So I bought this toy about three years ago.
It's a 66 Chevy short wide 4x4 with a small block 400 and an automatic.
After raggin the hell out of it, metal worms have finally made me tear it down to rebuild. (the cab floors were gone and the cab was settling)
I am trying to figure out what the rearend came out of.
It is NOT stock to this truck.
It is a GM 12 bolt, mounted on a ridiculous 7 leaf high arch spring pack. The spring perches have been remounted I am assuming to correct the pinion angle. (It also has 4" lift blocks.)
They have also been moved outboard one inch on both sides.
The previous owner (who did not build the truck) told me when I bought it the running gear was out of a '77 blazer. The frame numbers are from a '66.
I have searched on the web but can't find anything definitive.

So... anyone "in the know" who can help me verify what it came out of , I would really appreciate it... or maybe you could point me in the direction of where I could find it.

3896839 N -- casting number on the housing
E 4 7 -- date code on the housing
KAH 126W71 -- axle code on the passenger tube

Don't know what the gear ratio is as I have never had the cover off of it.
If anyone could help??????
Also forgot to mention the axles are standard chev 6 lug.

--------------------------------------------------------------------------------

Also posted my follow-up on other sites;

Just for giggles--- In desperation I called the local GM dealership and spoke to their parts guy. Gave him the info posted above... told him it was a 12 bolt w/six lug axles.Told him I thought 70's era.
He said he didn't have a book listing those numbers but could call GM and would get back to me.
Called me back about thirty minutes later and said " your differential is a 10.5" ring gear 3.73 ratio out of an 81-90 one ton truck or an 81-93 panel"
Ok I'm not real bright but there is NO WAY this thing has a 10.5" ring gear.
I am going to pull the cover and try to get the numbers off the ring gear.
Anyone have or have access to a Hollander interchange book????
Thanks!!!!!!!!!

i have a '55 1/2t rear, and it's ring is 9.3

Check post(rearend gear on '63 suburban).

Thanks for the replies!! I am going to pop the cover off and see if the ring gear is dated.
As to the "63 sub post" I went to the link several days ago in a search for code identity and American Classic axle code search would only go up to 1972. I was told this was a 77.
I searched for matching numbers in all years from 60 to 72 but no match.

Popped the cover... got the numbers off the ring gear.
it reads; 3817779 14 43 GM 2 71 1
pics posted of the teardown.. and some close-ups of the axle here: http://s676.photobucket.com/albums/vv130/JaggedEdge_album/

43/14=3.07. and i'd guess it's a '71