After doing a few launches with my new clutch, and i think messing something up with my stock rear, i know how touchy they are.

So i wanna know how much abuse can a 12bolt or 9'' take? With the supporting drive line, am i going to beable to do a 5000 RPM clutch drop on ET streets and just hold on for the ride?

I know its "shocking" the rear end that breaks them, and id say a 5k clutch drop throwing about 400 RWHP would be considered as quite a shock

But i also know my setup is pretty tame compaired to some people running these rears, so they must beable to take some punishment...

Anyone set me straight?

 

9" is stronger, but will rob more HP. I think injuneer is running a 12 bolt with 800 RWHP

 

I didn't break my 12-bolt with >700rwhp and 5,000rpm launches.

Rich

 

What is so different about the design on these rears that they can take 3x the tortue the stock 10bolt can? I know a 5000 RPM clutch drop with a heavy clutch and 300 RWHP can destroy the stock rear.

They are basically the same design but beefier parts correct?

 

Everything's Bigger.. I haven't seen a 12 bolt's internal's.. I have a 9" and the pinion gear alone is like 3x the size of a stock fbody rear.. Can't go wrong w/ either.. 9" don't have a abs option Unless you run the reluctor on the driveshaft like someone has done.. or you have Traction Control.. 12 bolt is a better option for those who would like to keep their Abs.. The 9" will cause your car to kinda ride like a tank over large bump's.. But on the hwy and all it's transparant.. I have pounded on mine and haven't heard a peep out of it.. Granted it was only 300rwhp.. But a street twin and 5K+ dump's..

 

There's more to it than just size, but FWIW:

Ford 9"
Ring Gear Diameter 9”
Ring Gear Bolts (10) 7/16” x 20 RH
Yoke/Pinion Spline Count 1.312” / 28, 1.500” / 35

GM "car" 12-bolt
Ring Gear Diameter 8.875”
Ring Gear Bolts (12) 3/8” x 24 RH
Yoke/Pinion Spline Count 1.625” / 30

GM 10-bolt
Ring Gear Diameter 7.5”
Ring Gear Bolts (10) 7/16” x 20 LH
Yoke/Pinion Spline Count 1.438" / 27

Rich

 

Well there ya go.. But its still bigger..

 

I have a Moser 9" with 4.71 gears, 244/250 Camshaft, MT ET Drags 28X10.5X15, qa1 shock package, Spec Stage 4 Clutch and I launch at 6200RPM. I ran a 11.41 Cam only at rockingham last weekend. I would never trade my 9" for anything and love it. I raised my launch and plan on leaving at 6400 and shift around 7500. Go with a 9" and of course you will need a driveshaft.

Joe

 

i'm assuming your talking LS1? w/ Rpm's that high a LTx would throw a rod quite far.. Not to mention the puter stop's at 7K.. Are you stock internals' other than the cam? Nice #'s..

 

Dam i bet thats quite a rush!

Your stage 4 taking the launches well? Are you pulling the front tires on launch? lol

 

I have a 9 inch in mine with a spool, moser axles, and strange gears,I stall the converter against the transbrake to about 4500-5000 and leave with a 250 shot to the already 500 rwhp with no problems except for a broken torque arm mount. rear end integrity has proven flawless