[goatwgn]

Originally Posted by azbirds

that doesn't make sense. All Firebirds with the 400 would have the 12 bolt then.

As well as any GTO from '64-'70.

[Formulajones]

Yeah that's where Pontiac/Buick/Olds dropped the ball. That 300HP deal for the most part followed true with Chevrolet products starting in 65 when the 12 bolt first saw the light of day. Don't know why Pontiac held onto the crappy 8.2 for so long, since Chevrolet only saw fit to use it in their low power passenger cars up through about 1971 or so. At least Pontiac finally wised up and intalled a Chevrolet 12 bolt in the 1970 F-body T/A and Formula for the first time, then it disappeared again in favor of the 8.5 10 bolts, which isn't a bad thing.

I've always thought BOP had some strange rearend choices throughout some of those performance models, especially the 67-69 1st gen Fbodies and the A-bodies up through 1970.

[goatwgn]

Originally Posted by Formulajones

Yeah that's where Pontiac/Buick/Olds dropped the ball. That 300HP deal for the most part followed true with Chevrolet products starting in 65 when the 12 bolt first saw the light of day. Don't know why Pontiac held onto the crappy 8.2 for so long, since Chevrolet only saw fit to use it in their low power passenger cars up through about 1971 or so. At least Pontiac finally wised up and intalled a Chevrolet 12 bolt in the 1970 F-body T/A and Formula for the first time, then it disappeared again in favor of the 8.5 10 bolts, which isn't a bad thing.

I've always thought BOP had some strange rearend choices throughout some of those performance models, especially the 67-69 1st gen Fbodies and the A-bodies up through 1970.

The Chevrolet 8.2 wasn't even as good as the BOP unit.

[Formulajones]

There are a couple of things I liked better from the BOP 8.2 compared to the chevy version, but both are subpar units for any real performance application in my opinion.

[JSPONT]

Originally Posted by Firebob

So I've been kicking around the idea of building up the 455 but I'm thinking that if I drop it in front of my M20 and 8.2 I'm going to have some serious collateral damage to deal with.
Does anybody think the clutch,trans and rear has a chance of living? Keep in mind that my psychological make-up will not allow me to not find out how much juice a car has. I know this about myself.

If you want piece of mind and never want to worry, you know what to do! A dana is heavy as hell, a nine inch is great but it is a ford product. The 12 bolt can be just as strong, look great and correct in your car.
I have a tko 600 and a 12 bolt(moser axels,easton posi) with drag radials. I am nor easy on the car to say the least, No rear end problems yet!

[Schurkey]

I keep wondering when the 9.5" 14-bolt semi-float truck axle is going to get popular in performance swaps.

The things are dirt-cheap, some have Gov-Locks which seem to hold up in the 9.5" version although Gov-Locks are fragile in the smaller designs.

Like the Dana, they're heavy as hell, and being truck axles they're all set up for leaf springs--but of course that'd change as they get appropriate brackets to install in the car bodies.

[Formulajones]

Originally Posted by Schurkey

I keep wondering when the 9.5" 14-bolt semi-float truck axle is going to get popular in performance swaps.

The things are dirt-cheap, some have Gov-Locks which seem to hold up in the 9.5" version although Gov-Locks are fragile in the smaller designs.

Like the Dana, they're heavy as hell, and being truck axles they're all set up for leaf springs--but of course that'd change as they get appropriate brackets to install in the car bodies.

The first drawback for a passenger car might be the 8 lug wheels

14 bolts are popular among the offroad crowd around here, Almost did that in my 72 blazer when I did the 6.0 LS swap but those 14 bolts around here are gold so I stuck with the truck 12 bolt and built that.

My 79 1 ton has a 10.5" 14 bolt rear with 3.73's, full float axles, it's one tough piece. Drawbacks are buying rear drum brake shoes that cost $120 a pop, then trying to find a big mack service station that has a lathe large enough to turn the drums lol. Thankfully I've only had to do it once in 15+ years.
The rear in my 05 duramax is an even larger ring gear, 11.5" I believe. Also getting into these later years you get into rear disc brakes which could be a plus for some people.

[archerytony]

I broke my m21 3x in one summer behind my 468 put a m 23 in it from autogear and its been great Im running a 12 bolt with 331 gears Like they say as long as your tires are spinning it is easier on the rest of the drive