COPO part #s and a 9"

[rod]

in the new Car Craft mag, the is an article on the COPO camaro. this car uses a Strange rear axle, which is captioned -think 9".
i believe that these cars are now reality.
if so, then i have this question.
if this car is, in fact, a "production" car, and since all Chevy cars have part numbers on the various parts included in the car, by extension the rear axle assy. should have a GM #. am i correct?
OK, since the nhra rule book says that to run in stock eliminator, the rear axle has to be corporate....i would have the [logical] choice of the original '56 axle or a 12 bolt. however if the new camaro uses a 9" ford style axle....which would be termed corporate, then i should be able to use a 9" ford in my '56 Chevy in stock.eliminator.
i am serious about this, this is most of an $1800 question.
your thoughts please.
thanks rod in AZ

[james schaechter]

I think Jeff Lee used similar logic to get a Dana in his AMC. I am pretty sure they aren't going to allow any of the new car stuff in older cars though.

What do you think Jeff?

[Jeff Lee]

The logic used by Rod is sound BUT I think all these new factory hot rods are all one part number approved at a time; i.e., the Ford 9" used is specific to the 2012 COPO and any subsequent COPO's ONLY.

In the case of my AMX, Chrysler bought AMC in whole in 1987. The Dana 60 was a regular passenger car production item for Mopar vehicles so once AMC was a Mopar vehicle, the corporate rear ends were allowed.

[JP]

So now you can use a Fiat rear end in the AMX?

Originally Posted by Jeff Lee

The logic used by Rod is sound BUT I think all these new factory hot rods are all one part number approved at a time; i.e., the Ford 9" used is specific to the 2012 COPO and any subsequent COPO's ONLY.

In the case of my AMX, Chrysler bought AMC in whole in 1987. The Dana 60 was a regular passenger car production item for Mopar vehicles so once AMC was a Mopar vehicle, the corporate rear ends were allowed.

[Jeff Lee]

Or Renault...

[aspen7709]

I asked this question @ SEMA last year. and BOTH NHRA AND GM both said "NO WAY!!!!!" The only way you get to run the "GM 9" is in the new cars ONLY. I spent over an hour talking with nhra tech there and gm people arguing my point and both agreed that this is an exception to the rule. Their logic..... "want to use the new parts ..buy a new car!" The same thing applied to the ford racers over the aluminum 9" center sections. You can ask Ken Meile and Rusty Hall how that turned out.

[Ed Wright]

They draw lines in strange places sometimes. Maybe they are trying to help sell the new cars, and get rid of our old crap.

[rod]

funny how you can run a non OEM trans or non OEM roller rockers in a 'stocker' but you cannot use a rear axle assy. which my brand uses in a 'production' car!!!!
rod in AZ

[Run to Rund]

The only good news is that the car will be a little faster with the 12 bolt than with the 9" due to the steep hypoid angle = drag of the Ford diff.

[Alan Roehrich]

Rod,
The only advantage a 9" would give you in your car is ease of changing ratios, and even then, only if you had spare center sections. A 56 Chevy Stock Eliminator car would not even come close to putting excessive stress on a good 8-1/2" or 8-5/8" 10 bolt Chevy, much less a 12 bolt. And any of those rear ends would absorb less precious torque and HP than a 9" Ford. The only limit to a 10 bolt for you would be that Richmond doesn't make anything lower than a 5.57 for it. If you need more than a 5.57 gear, you'd have to go to a 12 bolt. The upside there is you could use an aluminum spool in a 12 bolt, no one makes one for a 10 bolt.