Posi from a '66 bolt onto my '64?

[bepnewt]

Will a Posi from a '66 swap onto my '64?

-BEPNewt

[Bleach]

The two cars have different rear track measurements with the 66 being 3.4" wider.

[CTX-SLPR]

I don't think the 66's had the same model rear axle. If they did then you should be able to swap the whole pig out one for one. However like I mentioned earlier, I'm pretty sure the '66 has an access cover vs. a drop out pig.

[Bleach]

From the ROA site: Riviera Owners Association

1963 & 1964 - Ratio is stamped on the bottom of the axle housing - two numbers - one above the other. Example: 3 over 2 is 3.23-1; 2 over 78 is 2.78-1. Locking axle (positraction) is identified by "X" in a circle on bottom of carrier flange.

1966 - Ratio codes located on bottom of right axle tube 3 inches from cast housing "X" in circle means locking axle.

Sounds like the axles might be different.

[RivNut]

You'd need to set the posi units side by side and take a bunch of measurements. The length of the axles won't matter, the number of splines on the end of the axle will. Tomorrow I'll take a look in both my '64 and '66 chassis manuals and see how they're described, but right now it's time for this old coot to hit the hay.

Ed

[JZRIV]

Brian,

Sorry but the 66 has a totally different design rear axle. I saw that posi for sale too!

[bepnewt]

As always, a wealth of information. Thanks.

-BEPNewt

[CTX-SLPR]

What's the going rate for a 1st Gen 3.23 Posi these days?

[RivNut]

Since they're mostly made of unobtainium, the price is "what ever the seller is asking." Depending on how badly you want it, you'll know if it's a good price. When's the last time you saw one for sale? If you've already got the 3.23:1 gears, all you're looking for is the posi unit. You can bolt your 3.23's to any 3 series posi unit.

Ed

[CTX-SLPR]

Since they're mostly made of unobtainium, the price is "what ever the seller is asking." Depending on how badly you want it, you'll know if it's a good price. When's the last time you saw one for sale? If you've already got the 3.23:1 gears, all you're looking for is the posi unit. You can bolt your 3.23's to any 3 series posi unit.

Ed

More along the lines of selling mine to fund my 4L80E and 8.625in 10-bolt swap.

[RivNut]

Exactly. I was "Googling" some and found a two year old ad fein V8Buick.com for a complete drum to drum rear end from a '63 Riviera with the 3.23 posi. and the seller was asking $950 for the setup. That's probably gone up with inflation by now.

When I got all the goodies to install the 200-4R trans in my '64, I was looking around and found what I thought might be a complete solution for what I was running ( a .67 o/d, anything lower than a 3.42 is going to make the engine lug at road speeds) and that was a complete rear end out of a Ford Explorer. 59" bolt surface to bolt surface, same as the '64, and they all come with 3.73 gears, posi, and disk brakes. I figured the only thing I'd have to do would have mounting brackets welded on the housing that would allow me to mount it under the Riv. I'd also need a proportioning valve for the rear disks, but that shouldn't be a hill for a climber. For right now, I'm going to run a set of 3.91 open gears in the '64 housing. Perhaps when I want to finance the complete rear disks w/ posi, I can sell the 3.91 and have some change left over.

Ed

[CTX-SLPR]

I found a guy parting out a '65 Riv and had him cut the brackets off of the rear end since it was just scrap steel to him after he sold the pig out of it. I'm planning on using a 91-93 B-body sedan rear axle since they are near the right width, 5x5in bolt pattern, had 3.42 gears available, and call me nutty but have the ABS sensor placement that matches the 94 Impala SS ABS unit I have on the shelf. It should fit with the addition of the same generation Caprice 9C1 steel wheels which will push the track out slightly to better match the spacers I might need to run to get the stock wheels over the 98-02 F-body calipers on the front.

Good to know I could finance the whole thing (assuming a buyer) and then some with selling the original rear drum to drum.

[1965rivgs]

The 3:23 pigs should not be hard to find or "over the top" pricey. It is very common to find those gears in the Dynaflow equipped cars and those gears will swap into the more common posi carrier. So, if one finds a 3:07 posi from a `65 and 3:23 gears from a `63 open rear the gear sets will swap back and forth. The 3:42 and higher gear sets are another story. The carrier is different due to the thickness of the ring gear and both the carrier and gears are very hard to find....more so the carrier as one can use 3:42 gears from a GS Riv right thru `70 and up. The higher gear set carriers basically only come from the `65 GS cars...or a Buick ambulance!

Quick story...I bought a `65 GS parts car and just before I was about to leave the seller told me he had some parts left over from a `66 Wildcat he had recently bought and immediately sold. I hesitated at first because I was pressed for time but he said if I did not want them he intended to throw them in the trash. He walked me to a small room off his garage and there on the shelf was a `66 Quadrajet manifold and carb and an NOS 3:91 gear set. Turns out he bought the `66 Wildcat from a fellow who was weekend drag racing it. We`re still friends after all these years..what a guy! Moral of the story....make time when sniffing out old cars and always, ALWAYS ask if the seller has any extra parts..preferably before you close the deal!

Tom Mooney