Ok, I tried searching but can't find a solid answer. my question is, how much power can these rears handle when fully built behind a manual tranny with street tires, mainly street driven with the occasional trip to the strip? I read that the 9 bolt is stronger, how much?
I understand that fully building them costs about half as much as a new 9/12/60, but if a 9/10 built is all I need thats a good chunk of change saved. thanks

 

The stock 9 bolt is stronger than the stock 10 bolt. The ring gear is larger and the Borg Warner posi has 4 pinion gears instead of the 2 pinion gears in the 10 bolt. The 10 bolt can be built stronger with a new Eaton posi, but the 9 bolt will probably still be stronger. As for what they can handle, that's hard to say. There are a lot of things that have to be considered. The engine power, trasnmission, traction, suspension and many other things will have an effect on how the rear end holds up.

 

does anyone have ballpark numbers?

 

are you talking about a nine bolt being stronger then a 8.5 10 bolt?

 

i think you mean 7.5 inch 10 bolt

 

Go with the 9-bolt and if your that kind() of driver you would break whatever
rear is back there.

 

I am talking about 9 bolt vs 7.5 10 bolt, just wondering how much power each could handle, fully built, behind a manual tranmission with street tires, mostly street driven with the occasional trip to the strip

 

agreed

 

9bolts can be rebult but there is no aftermarket parts for them only real exception is the performance support rear cover girdle. this will help. the 9bolt is stronger than the 10bolt it has shorter distance between caps in the rear allows for less deflection. u can replace the 9bolt posi with a new stock one but they are only stock replacements. there is no aftermarket posi's for the 9bolt. i believe the 9bolt also has 28spline axles stock vs the 10bolts 26. also stated is the 4 pinon gears vs the 10bolts 2 pinon gears. this allowes it to handle 30-50% more tq vs the 10bolt. this is stock for stock. i stock 9bolt is rated for 297hp and 300ftlbs tq i believe. and the 10bolt was way lower than that. i beleive thats at the wheels too.

as far as fully built behind the manual trans.... umm either arent gona last long. a auto trans is ALOT more easier on the drivetrain than the manual. also depens on ur manual trans u have and the rear gear ratio. most of the stock T5s cant be built to handle more than 300hp anyway so it doesnt matter wat rear u have lol. as stated the 9bolt has its advantages over the 10bolt but the 10bolt can be built to handle 400rwhp thanks to the aftermarket. if ur easy on the rear and dont do any 5k clutch drops a rebuilt stronger 10bolt could last a few yrs depending on the components u use to rebuild and how u drive the car.

to build a 10bolt ur gona need moser 28spline axles. weld the axle tubes (matter of preference, most will say do it) u will have to upgrade the posi to a auburn or eaton. eaton is better but more expensive. i believe they also have lockers i could be wrong. and ur gona need a installation kit that gets rid of the weak seals/crush washers etc. i would upgrade the cap bolts to some ARPs, and get a support girdle to help with cap preload. get this installed correctly within the clearances recomended and you should be good for a 400rwhp 10bolt.

 

no I meant 8.5, I tossed the 7.5 that was in my monte for the 8.5. I always thought the 7.5 was junk. all this third gen stuff is fairly new to me.

 

I've seen this 400rwhp for the 10 bolt a couple times now, but is that with an auto or a manual?