In a "normal" car it always goes on the rear, but depending on the car weight bias, tires & brake system it's not always the case as most drag cars aren't normal when it come to brakes and especially tires. On my 67 the weight bias is 49-50%, it has M/T sportsman skinnies in the front, Good Year 32.4 x 16 slicks, Wilwood disc brake (Drag) in the front and the big Pro Street set up in the rear. With the proportioning valve in the rear line my front tires would easily lock up, I had to move the valve up front to stop this from happening, with the valve removed from the rear the rear tires still will not lock up before the front.
Even with the weight transfer caused by braking the bigger rear tires can still offer alot more traction than the skinny front tires can. If the system works the way it is and your not having problems with the back tires locking up it was done that way for a reason.
67 Pro Street Fastback
Full tube chassis, IHRA & NHRA certified
526 c.i. C & C Boss 429 Hemi
Littlefield 14-71 High Helix Retro, Kobelco K-9 rotors, 22% over
Enderle alcohol inj.
MSD-10 Plus ignition & controller
9" rear, 3.89 gear
Full exhaust with 6" hand made mufflers