[RICK LAKE]

Lippy A normal jag rearend will handle 450hp and 450 torque. This is old spec numbers and doesn't say what the stub shaft spline # is. Could be 19 spline or 27 spline. I know a couple of guys running 19 spline with 700+hp and torque. You can get many years from it. The limits are ABUSE and what kind of tire are you running,( tire wear number).
Lets talk abuse, this is quick. 3,000 rpm clutch drops and the rearend walking in the back of the car will break the carrier for sure or twist the stub shaft spline. These stub shafts are softer metal than chrome moly for the stub shafts. Adding a 30 spline carrier will increase the load factor by 30%. Adding a Watt's linkage would also be a possible opition to help control the rearend movement. You didn't say which rear brake kit you are looking at? inboards or outboard brakes? I really doesn't matter. You can have a 600ft+ of torque. You need the rearend to handle the constance load which is where most of your driving will be. If you want to save the rearend, use the right foot to control the problem and forget about it. I autocross and roadrace, I over built the jag housing with a locker and chrome moly 30 spline stub shafts. It also has a rearcover that supports the caps that hold the carrier in location. 15+ years and have not broken this rearend yet. Abuse, yes alot and running soft tires with a 200 wear. Rolling on and off the throttle will help extend life. I am sure that Doug at ERA will built you a rearend to handle your power specs. A clutch will also help save the rearend if it's soft and has a spring hub for the disc. The rest is suspension setup and alignment. You can also move the power ranges for HP and torque around by where the camshaft is setup. Advance or retard the camshaft timing could add or kill 20 to 40 HP and 10-30ft of torque real easy. Talk to the motor builder. Exhaust is the last thing, depending on side pipes and how much you like hearing. Quieter pipes kill power, up to 50 HP and 40ft of tork. Here enough info to keep you busy for a while. When this is done, we can work on tire pressures. Good luck. Rick L. Ps the word "TOY" was used here. This car is the farthest thing from a toy. We have lost a few guys from the CC family. RESPECT it and enjoy. Also look at possibility of a driver school for a couple of days to get used to the car and understand what you really have. I have about 600ft of torque and 540 HP. An increase from 448ft and 348ft. Car is not as fun as it used to be. Some times less is better instead of more.