3.91 posi for a 1964 Wildcat WANTED

4-Speed · March 25th, 2009

OK, I know this is going to be tough, but I am looking for an original 3.91 posi unit for a 64 Wildcat/Electra/Riviera. If you have one or know of one for sale, please let me know!

Thank you,

Matt

imported_JohnD1956 · March 25th, 2009

Does one even exist? Good luck.

4-Speed · March 25th, 2009

John, yes they do, though they are rare. In my 64 parts book, it shows part number 1396098 as being a positive traction diff. package for ratios 3.36, 3.58, 3.91, and 4.45 - all special order. Not really interested in a 4.45, but I do want a 3.91.

imported_JohnD1956 · March 27th, 2009

Presumably this would have only been available on the standard shift cars? How else would we identify one if we happend accross one while scavaging older recycle yards?

BJM · March 28th, 2009

John,
I recently inquired of a 63 Pontiac posi seller and he said that Olds/Pontiac were the same but Buick was totally different. IF, (big IF) you found a 64 Wildcat in a salvage yard with a potential 3.91 it would probably be a specially built race car and the rare and desirable parts would be long gone.

So - yes we would be limited to swap meets I believe such as Hershey / Carlisle - other BOPC meets like the one in Chicago this weekend. Matt, do you have a photo of a 64 Buick rear pumpkin with posi in any gear ratio?

4-Speed · March 28th, 2009

John, I have heard of them installed in Rivieras, as well as stick shift cars (my black 4-speed Wildcat has one), so I think you could order a 3.91 for any full size car, even in an Electra sedan! Buick stamped the gear ratio right on the bottom of the axle housing, but if in a salvage, it'd be very tough to find or see if the car is on the ground. The stampings are usually fairly light, so if the housing is rusty, the numbers would be gone. An easy way to tell is to spin the tires, but again, in a salvage most of the time this is impossible. The cast-iron center section (carrier) for the posi units has a small stamped circle with a stamped X in it to denote it as a posi, but again, you have to be either under the car to see it if it is still in the housing, or have the center section out and then visually inspect it. With the unit out, you can count the teeth or read the numbers on the gears to get the ratio. Heck, it doesn't have to be a 3.91, if you find any 63-64 Buick posi units, get them. Unlike the many Pontiac posi cars, it is odd that with the torque of the 401s and 425s more people didn't get the posi rear ends.

Bryan, I have many I can get a photo of, but I am at home right now. When I get to the shop, I will post one. That is one thing you will find out with the Buicks, most of their parts are for Buicks only, including all the stick shift stuff, posi units, rear ends, etc. That's what makes them so d#%n cool!

Thanks again!

Matt

imported_wildcat1562 · March 29th, 2009

i have 2 such cars here
for parts
one is a 64 lesaber 401/ 3spd car that had the floor shidt in it and was a 2dr
nothing else,
and the other is a 64 wildcat convertable that had a 4spd in it
and chance these might be the ratio's
and if they are
how would i find out without taking them apart
they are both posi as well
Greg

TOPCAT · April 15th, 2009

What is a set worth if someone might have a set they could sell ?

Peace WildBill

4-Speed · April 15th, 2009

WildBill, probably whatever one would want for one, it's not like people have been knocking my door down to sell one.

So... do you have some good news for me?

Tell you what, just throw it in the trunk of that white car I have been after and we'll make a deal! hehe

Thank you!

Matt

TOPCAT · April 19th, 2009

Matt, i am in the process of evaluating my needs as far as spares for my Wildcats. I may have a 3.91posi in excellent used,read to run condition. No promises yet but you will be the man that's first to get them......

I will be in touch.

Peace WildBill