Square body shock locations question

[pacman1967]

I am rebuilding the rear suspension on my 85 c10 SWB. I plan on running new stock leaf springs, Caltracs, an anti-roll bar and a set of double adjustable shocks, most likely QA1s. Is there any benefit in relocating the shocks? If so where have people found to be the best position?

The truck has a supercharged 350 with 5lbs of boost running 450-500hp and similar torque numbers at the crank. It has a 10 bolt with 4.56 gears and a posi unit. I have lowered the rear of the truck 4" with spring locators and a taller shackles. I am looking to lay down some good 60' and 1/8th mile times. Thanks in advance guys.