Value in 10 bolt to truck 12 bolt swap?

[nikwho]

So, I've read that the truck 12 bolt rear axle's have the same pinion diameter as the 10 bolt rear axles, and that they are smaller than the car 12 bolt pinions, as well. I have a friend that will trade his 1980 C10 12 bolt rear end for my 1986 C10 10 bolt rear. I am building a '68 GMC that will have a healthy 600HP BBC. I plan to drag race it once or twice a year, enter a couple of autocross races per year and primarily drive the truck on the street. Most trucks are a little easier on rear ends than cars, due to the f/r weight distribution. So, right now I'm trying to decide if It's even worth the time to swap a 12 bolt truck in place of the 10 bolt. I figured that if the pinion shaft diameter is the weak link, is it worth having the additional unsprung weight of a 12 bolt axle, or should I just stick to my 10 bolt and build it?

I've got about a 2,600-2,800 stall converter and will be leaving using just a foot brake, no trans brake. Also, I will be running some 27x11" Goodyear slicks, with 4.10 gears.

Thanks!
Nik