Yeah, my engine guy has a 66 GTO bracket car. The 12 bolt was all he needed til he got passed the high 9's. Then he wiped it out. So now he recommend's something stronger, for anything below a real high 9.
He also chose the big, chunk type Pontiac. What were they, something like '58-'64 ? But as you say, setting one up ain't easy or cheap. A 12 bolt or 8.5' ten bolt will be strong enuff for me.
For those interested, this place sells parts for the big Olds/Pontiac rear.
http://fabcraftmetalworks.com/
I wonder how much the big rear will slow a car down ? With the extra rotating weight, it has to take a little more hp to turn it, huh ?