rear end questions

[GM Muscle]

i have a 9" housing out of a torino that i was concidering under my 69 camaro. I have a few issues with the 9" though. First, all i have is the housing and the wrong lug pattern axles, second, i have a set of 4th gen camaro rear brakes i want to use and im not sure what its going to take to install them on the 9" backing plate wise, third its going to be pretty pricey to build this thing up unless i can find a fairly nice used 3rd member and finally the rear end is the correct width for factory wheels and tires but im running zo6 wheels which require spacers

the other option i was concidering was a 12bolt out of a 73-87 chevy pick up. and for a few reasons. 1. i can buy a fairly built one off my rock crawler buddies with gears and all for around 500 and just get axles with the right bolt patter for 3 or 400. 2. its going to be the right width, shich means no spacers and 3. im under the impression my brakes are going to "bolt on".
I have read some bad things bout the truck 12bolts though as far as strength goes. i plan on reaching the 500hp mark and only running street tires in an auto-x manner. no drag racing.

so what do you guys think.. i mean id love to just throw down 2600 and be done but id like to buy control arms and such. what do you think the best route for me is going to be?