Thank you all for the information. However, I'm still cunfused because of the other questions being asked. Do am I correct in saying that none of the 8.5" rears will fit correctly into my 1966 A body?

So what kind of news it that anyway? I was looking for someone to tell me I didn't just toss another 8 big ones out the window sheesh. I'm learning why people like myself always seem to tale a life time to complete a project. We back step so much because when we decide to "change" projects we end up with something where nothing we have will work for the new project. That goes for new coated headers, sway bars, and so on. If i had the room I'd just keep them both. But you see, it's not that simple since these two cars are only just that. Two projects out of the others I have. I'll trade them all for a nice late series Accord in say off white. Any takers ??? http://forums.performanceyears.com/g...icon_smile.gif

Thank you all for the information. However, I'm still cunfused because of the other questions being asked. Do am I correct in saying that none of the 8.5" rears will fit correctly into my 1966 A body?

So what kind of news it that anyway? I was looking for someone to tell me I didn't just toss another 8 big ones out the window sheesh. I'm learning why people like myself always seem to tale a life time to complete a project. We back step so much because when we decide to "change" projects we end up with something where nothing we have will work for the new project. That goes for new coated headers, sway bars, and so on. If i had the room I'd just keep them both. But you see, it's not that simple since these two cars are only just that. Two projects out of the others I have. I'll trade them all for a nice late series Accord in say off white. Any takers ??? http://forums.performanceyears.com/g...icon_smile.gif

The cars the 8.5 was offered in are wider then your 66. The f-body ones have leaf springs while your 66 has coils and a 4 link type setup. The only way to make one work would be to find one that is as close to the width of the stock 66 width as possible and relocate the mounting points.

There are 8.5” rear ends that will bolt in to your 66 a-body. They are out of 1971-72 Buick & Olds a-body cars. There may be a difference in width of about one inch, but this usually doesn’t cause any problems.

Dont forget the 70-72 Monte Carlos. I believe they had the 8.5s. 12 bolts too.

1966-67 Pontiac A-body has got the same width on rear end as any 1968-72 A and G-body.

I have a late 70 OLDS 8.5 rear in my 67 and it fits fine.

Thank you everyone for all the information. What I'll do then is look for a later "A" body rear end. Pull the carrier and gears out of the short one I built for the Firebird. And, have a shop install them in the later "a" body 8.5". Unless that is the same parts that fit the 8.5 O got from the Nova will not fit the "A" body 8.5" in which case I'll just stomp my feet and start over again watching good money chase bad money. http://forums.performanceyears.com/g...icon_smile.gif Good day friends. Mike

Take a Chevy C-clip posi and your 8.5 Chevy gear set, grind 1/8" off of the out side edge of the ring gear teeth, grind case so gear set will pass through where rear cover fits. Install metric bearing onto pinion ,the one that goes behind pinion gear only, the other bearing is standard. shim accordingly, use Chevy yoke. There ya go, I've done many of these. Pontiac Gregg

Hi, I posted an answer to your 8.5 question and forgot to select e-mail otification. Pontiac Gregg

Might just double ck the width of your '66 rear. Not all '66 LeMans-GT0 rears were the 1" narrower variety like the '64, 65 & early 66 8.2's. In reviewing this whole post,the best bet is the complete 8.5 A-body rear swap. It's a bolt-in, but one will have to shorten the stock driveshaft 1".

Advantages of the 8.5 A-body:
- Overall strength... no small pinion bearings & flexing in the nose of the housing upon loading of high torque application. Unless one is lucky to have a rare nodular case 8.2, the 8.2 makes little sense for strong performance use.
-No sealed bearing axle bearings to seize & eat up axles, instead running taper bearing axle bearings, they'll run forever.
-much more affordable quality gears in wider range of sizes. Same with carriers, wide range of posi's & spools.

[This message was edited by ol' Pinion head on March 14, 2004 at 03:59 PM.]

I have what I believe is a 70-72 Olds 8.5 in my '66 GTO.

It is definitely an 8.5 (every piece of the thing has been replaced, and all of the parts are for an 8.5), no C-Clips, was originally 2:73 open.

Fits like a glove.

You will need to use a rear end from a 71-72 cutlass or buick skylark if you want to put an 8.5 in your car. I have a couple of these to build if you are interested.

RR67 how wide is that Nova rear over drums? I have been thinking of putting 8.5 in my 67 Firebird. The car is 10k car with 4.33 and I don't want to brake original.i been thinking of racing it.

Sounds good, tell me more about what you have and where your located? e-mail me at [email protected]. And, please provide an e-mail address in return. I tried a message to you but I'm not allowed in your message group

Mike in Oregon