[rfb92345]

I have often thought about this myself. There are special gear carriers allowing you to run 12 bolt gears in a 9", or something like that. I refer back to Brians question of why would you be concerned about 3%. The cost of building one of these low drag 9" rears or even a 12 bolt or Dana 60, gets expensive real fast. I think I could take the money I saved and make up that 3% in the motor a whole lot easier. I think some of this stuff has merit when building a total package within the constaints of a rule book, but like Brian says, why is it of concern in a bracket car. I'm with ponjohn, also, I'd just rather know that its going to hold together, I'll get the 3% somewhere else cheaper.

[screamingchief]

Not every 9" ford rear is bulletproof...


Especially if your refering to OE cases,you better know how to choose the right ones or you could learn about this the hard way.


The folks most concerned with this issue are those looking for every .001-.0001 of ET,and have optimized virtually every other option available to them within the rules of the class they race in.

Say super stock or comp eliminator classes.

The area of concern in stock 9" carriers is the pinion support bearing casting,some of the stock cases are way too thin and too weak to risk in hi-po use,aftermarket cases are far superior to even the OE "N" cases,which are the best OE choice.

And yes strange does offer a drop out 12 bolt centersection to fit a 9" ford rear housing,solves the "3%" issue for those who need to be concerned enough to think about this.

Here are a couple pics to show the weak area for the 9" and such,and some info on the 12 bolt dropout deal.