What is the weight diff. between the two ? I have been told the 12 bolt weighs less but by how much ?

 

http://web.camaross.com/forums/showt...ghlight=weight

 

From that thread:
12-bolt: 170lbs
9-inch: 217lbs

So 47 pounds heavier.

At what horsepower level, or 60' time, or whatever would be an appropriate measure, should one start to seriously consider the 9" for its added strength?

 

My 9" weighs 190ish with an aluminum center section and steel spool.

 

^ ^ ^ a spool weighs less than a functional diff though, right?

 

Yeah, it does. My stuff may weigh a tad less than that. That is UPS scale weight, all 4 boxes added together. So it may be less. Ill let you know tomorrow. The aluminum center section weighs less that the nodular one by 15LBS, and I am not sure about the stock ford 9" setups. The 217lbs calculation was with a stock center section i believe.

 

So one last question, what is the weight of a factory 10 bolt ?

 

According to this thread, http://ls1tech.com/forums/showthread...ley+fab+weight, there is somebody in there that said that his 10 bolt full off fluid, and still totally complete with backing plates weighed 166.

I just got my stuff weighed out of the boxes and my 9" weighs 186lbs, but like I already stated it has a spool, aluminum center section, and the heavier 35 spline axles. It also does not yet have the backing plates put on either.