Ok, looking for a little info on on doing a 9" swap. My current rear end is a factory 10 bolt with a Yukon dura grip carrier, upgraded 28 spline motive gear axles and 3:23 gears. The car is lowered and will be mostly a street car/ occasional autocross. Just wondering if the current rear end will be ok or is the 9" a needed upgrade. Motor makes about 450hp. I have been talking to the guys a quick performance and would go with one of their bolt in housing and axle packages if I need to upgrade. I have heard putting a 9 " in a lowered car will cause some clearance issues with torque arm and gas tank? Any insight or recommendations are appreciated.

 

The 9" doesn't fit these cars all that well.

Most of them (don't know about QP) have trouble with hitting the area right below/behind the back seat, where the torque arm lives. Don't think there's any problem with the gas tank but I could be wrong. (well, I'm WRONG, with a capital R; but beyond that, mistaken in this particular matter)

You might have better success with a 12-bolt. 450 HP isn't all that much power, esp not compared to big blocks. A 12-bolt should have no problem with it. Only advantage the 9" has over that, is the ability to change gears faster. If you're not going to be doing that, it offers few real benefits. The 12-bolt fits these cars altogether better, has lower loss, and weighs less. Cost is more or less the same.

 

I looked into the 12 bolt idea. Price to have one built for my car was about a grand more. That idea is off the table. Maybe just put a set of better gears and hope it lasts.

 

Than what?

 

Quote for the 9" was $2250 shipped fo my po box in the states. Price for the 12 bolt was $3100. Then i have the 35% exchange rate up here in Canada.

 

Sounds like you're comparing the price of a more or less fully assembled 12-bolt to a 9-bolt housing w/o chunk or axles. Hard to say about brakes in either case for example.

Exchange rate AFAIK is not a factor... it affects both choices equally.

Butt hay, it's your decision: you know better than I do what your situation is.

 

The 9" is a better rear by far than the 12 bolt, and it fits fine except where sofa mentioned, the top corner of the tunnel by the driverside rear seat. Idk about midwest's mounts, but the more common Moser torque arm mount will smack the floor pretty good right there. It will clearance itself and eventually.stop hitting but leaves a nice dent or sometimes a small hole in the floor.

 

The $2250 for the 9" was a complete housing axles and center section. Just needed brakes.