10 Bolt vs. 12 Bolt - HELP

[morpwr8]

Ok, here's the question...

To build up an 8.5" 10 Bolt or go on the search for a 12 Bolt?

A buddy and I bought a 71 Skylark 2 Dr HT from an old couple in Chicago (original owners, etc...) and we're looking to do some light drag racing. It's got a straight 6 which we're pulling in favor of a 455 we got and that leaves us with the weak link...the rear end. It's got an 8.5 rear which from what I'm reading CAN be built to handle this motor and task, but I'm looking for folks with knowledge to pipe in here and either reassure me or smack me upside the head.

We figure that getting a built 12 bolt will put us in the $1200 or so range...If we have a rear end guy in the area build our 10 bolt, it'll come in at $800 for a new posi unit, bearings, seals, labor, etc...

Any insight would be appreciated.

Thanks,

Bob-

[Restorer32]

This is an antique car forum. Apparently you wandered in here by mistake? Now if you would like to restore the Buick I'm sure folks here can be of great help. Seems a shame to tear up a nice original car.

[joe_padavano]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">This is an antique car forum. Apparently you wandered in here by mistake? Now if you would like to restore the Buick I'm sure folks here can be of great help. Seems a shame to tear up a nice original car. </div></div>

Wow, way to encourage a newbie. Last time I checked, 1971 was over 25 years ago, making this car eligable for antique plates in any state. Also, this is called the "General Forum".

As for the rear axle question, unless you plan to run slicks, the tires will break loose before a properly built 10 bolt will break. If you do go with a 12 bolt, be wary of the Type O axle. These were unique to 67-70 Oldsmobiles and have a 12 bolt cover but only an 8.5" 10 bolt ring gear. Many vendors advertise these axles as "12 bolt" and charge accordingly.

[1937hd45]

Bob, Welcome to the Forum, forget about the 10 oe 12 bolt, take a tip from NASCAR and put a 9 inch Ford under there, its the best way to go.

[novaman]

Joe, you got to remember that this fourm is hosted by an antque car club, not a street rod, or drag race group. We have some members that are extremely dedicated to the restoration of motor vehicles and unfortunely even in person chasitze someone for making a car into a street rod. I say unfortunely because I've known of some cases were that person also had a very nice restored vehicle sitting in the garage, that being chewed out like that isn't good for our image. It's also enough to drive that person away wether he currently has a restored car and interested in joining now or gets one in the future and looking to get invovled remembers back and say the heck with those snobs. Fourtunely the majority of the membership isn't that outspoken even if they do hate to see an old car truned into a street rod.

[novaman]

From the Antique Automobile Club of America's Policy & proceedure manual.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> The aim of the AACA is the perpetuation of the pioneer days of automobiling by furthering interest in and

<span style="font-weight: bold">preservation</span> of antique automobiles and by promoting sportsmanship and of good fellowship among all AACA

members. </div></div>

This guy's question does go against that. That doesn't excuse the first response he got either.

I feel it is his car to do with as he sees fit. I build drag cars for a living but fortunely I only build dragsters. I shed a tear when some of the guys bring in what would have been a nice car if it hadn't been butchered.

As for the rear end for this car, a Dana or a Ford would work. The Ford would let you change ratios a lot easier. Just make sure it has a back brace so the tubes don't get twisted.

[joe_padavano]

At the risk of taking this tread off-topic, I have to admit that I feel the 60s and 70s muscle cars are meant to be raced. Frankly, I think that's better than letting a chalk-mark-and-paint-dab restoration languish in a garage only to be trailered to the annual show. At least the guy is starting with a six cylinder car, not a GSX. The way I look at it, I think keeping the car functional and occasionally running it on the strip (as God and GM intended) is a better "preservation" than seeing it destroyed in a Progressive Insurance Company ad (for those who haven't seen it, Progressive crushes a 71 Skylark 2dr with a "meteor" for a TV commercial).