12 bolt or 9 inch

i have a 84 z28 camaro. which rearend is best fit to handle brute power. im building a 383 cam 240/250 @50 041 heads dual plane intake 700 holley dbl pumper 2 stage nitrous kit. behind it will be a 700r4. it will run on pump gas ans spend more time on the street than the strip. i have the 7.5 with 4.10 gears. i thought about welding the axle tubes together, going with a hardened cover and new axles. by doing all of this will i be wasting my time. thanks any info will be greatly appreciated  

Not so sure about your combo being "brute power" but if you add some strength to your ten bolt 7.5, your 700r4 may be the weak spot. The main factor in all of this is how much traction you will have. If you build a strong motor and have sticky tires, the drive-line will take the abuse.  
Jim
70 El Camino
461 solid, m20,
pics in readers rides

so canted by what means should i stiffening up my drive train? in particular the tranny since you say it might fall victim first. i plan on running drag radials. first stage is a 100 shot then on the second 150 shot. im foot braking! or do you know any company thats makes a solid 700r4 that handle my application?  

I do not use an automatic so I can only go by what I have heard and read. In regard to that, both the 700 and the 200 should be upgraded in high torque applications.(I'm assuming you want to use a OD trans) The 200 appears to be the stronger of the two when built. In the March 09 issue is an ad for a trans builder with a contact address. I would suggest giving them a shout about your combo, here is a link. geagstar
CHP has done an article on building the 7.5 rear for performance. It was not that long ago, you may want to check that out. I would think that setup may suit your needs and save you some bucks. The current issue has a great article about the Moser company. I have no doubt their twelve bolt will handle what you plan on but you pay for what you get here.  
Jim
70 El Camino
461 solid, m20,
pics in readers rides

wich ever you come accross first. if i were you i'd KEEP the limited-slip unless your also investing in rack-n-pinon set up, my dads got a 68' full spool cant keep it in a straight line too much understeer with stiff springs and stock steering