[JSchmitz]

Originally Posted by Formulajones

If I remember right he was running a set of M&H DOT stickies on it which were legal for the stock class at that time.

(Off topic warning) I just bought a set of these. It'll be a few months before I get to drive it. They look good! Lol!

[Formulajones]

Originally Posted by JSchmitz

(Off topic warning) I just bought a set of these. It'll be a few months before I get to drive it. They look good! Lol!

They work pretty good. I like the vintage appearance of the bias version I'm planning on grabbing a set for black steel wheels for that day 2 60's look.

[tekuhn]

Originally Posted by Kenth

1966-72 Pontiac A-body uses the same rearend width.
1964-65 was 1" narrower overall width.

Chevy A-body was different, 1964-67 was the narrower style, 1968-72 was 1" wider width.

FWIW

This is absolutely true. Pontiac used the narrower housing '64-'65, and went 1" wider in '66. Chevy used the narrower diff '64-'67 and 1" wider '68-'72. The spring perches and shock mounts are all in the same position, even though the spring perches switched away from the bolt and clamp at some point. I have swapped a '65 Chevy 12-bolt into a '65 LeMans no problem. I just had to use a hybrid u-joint to mate my driveshaft to the Chevy pinion yoke.

[drewm]

Originally Posted by tekuhn

This is absolutely true. Pontiac used the narrower housing '64-'65, and went 1" wider in '66. Chevy used the narrower diff '64-'67 and 1" wider '68-'72. The spring perches and shock mounts are all in the same position, even though the spring perches switched away from the bolt and clamp at some point. I have swapped a '65 Chevy 12-bolt into a '65 LeMans no problem. I just had to use a hybrid u-joint to mate my driveshaft to the Chevy pinion yoke.

So theoretically (and also in reality?) I should be able to use either an early narrow rear or a later wider rear? I ask because if I decide to use an aftermarket 9", they have narrow rears listed as 64-67, and wider rears as 68-72, obviously using the chevy models as their width specs.

[tekuhn]

Originally Posted by drewm

So theoretically (and also in reality?) I should be able to use either an early narrow rear or a later wider rear? I ask because if I decide to use an aftermarket 9", they have narrow rears listed as 64-67, and wider rears as 68-72, obviously using the chevy models as their width specs.

The only difference should be moving the wheel 1/2" per side.

['ol Pinion head]

Hard to beat a built up bolt-in axle 8.5 A-body rear for a foot braked A-body streetcar that will never see 1.40 60 ft times on slicks. Tougher than any 8.2 10 bolt or Olds type "O", More pinion support than factory 12 bolts, & a more affordable core. Also don't have to deal with c-clip axles, converting to aftermarket tapered bearing bolt-in axles & hsg ends.

Ford 9"s have their place but they are not the solution to problems that do not exist. Have the actual need to leave on a trans brake in a fairly quick bracket car, one that runs different length tracks or you're changing out different height drag tire/wheel combinations, a very well built 9" makes sense.

[tekuhn]

Originally Posted by drewm

So theoretically (and also in reality?) I should be able to use either an early narrow rear or a later wider rear? I ask because if I decide to use an aftermarket 9", they have narrow rears listed as 64-67, and wider rears as 68-72, obviously using the chevy models as their width specs.

Moser, or whoever, should be able to confirm the spring, shock, and control arm mounts are spaced identically on either version. After that it's just up to you to decide which is most beneficial for the wheel back-spacing you have.

Here's a worthless story: I bought a 12-bolt from a guy back in 1986 for my '65 LeMans I was building. I knew nothing about the differences in the widths. It was a '68-'72 Chevelle unit, open carrier with highway gearing - $75.00. Got it home and started measuring and figured out it was 1" wider than my 8.2". '65 LeMans does not have generous tire clearance by any stretch of the imagination, so I took it back and kept searching. A couple weeks later I spotted a '66 El Camino in a salvage yard with a 12-bolt. Went inside and asked for a price - $150 if I pulled it myself. I showed up the next morning at 6:00am before work with a borrowed pick-up truck and tools. I got everything disconnected and drug it out from under the car, but needed help loading it into the back of the truck. Found a yard worker and asked for his help. First thing he noticed was the set of traction bars on it. He bent over one drum and asked me to hold the other one. He tried to turn his drum and mine moved too. He says to me "this thing's got a posi in it". I tried to look calm and shrugged and said it appears it might. He was quiet for a minute and then he says "You made a heck of a deal!". I couldn't get out of there fast enough. Got it home and started counting turns of the pinion - 4.11 gears (37/9). Still have the diff and the car. I'd gladly take the $75 one back too if I could.