Simply switching to discs will not really 'upgrade' anything. What pressure will you run at? Can your vac supply it? How many sq in of rotor do you need? What about pad surface? If its an engineered kit, OK, someone did the math for you. If you just want to 'add some discs' then how do you know you improved anything?
Disc brakes fade, warp and have the same issues as drums so simply switching will not 'upgrade' anything. Most tractor trailers (60,0000+lbs) still stop with drum brakes.
If you want to make your truck safer then put in separate front/rear brake circuits. NHTSA data show that one single change is the most significant safety upgrade (and the reason it was mandated in the 60s-70s Federal Motor Vehicle Safety Standard 105-68 and 105-75) you can do.
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www.tm9-801.comSince my G506 will be a daily driver I though about upping the brakes from drums to rotors (ie get new axle housings)... but ruled it out after reading NHTSA Report Number DOT HS 806 359 regarding brake improvements in US vehicles and the pure cost involved. There are the two stats that really surprised me: http:http://www.nhtsa.gov/cars/rules/regrev/evaluate/806359.html
Dual master cylinders annually prevent 40,000 accidents that would have resulted in 260 fatalities, 24,000 injuries and $132 million In property, damage. They add $17 to the lifetime cost of owning and operating a car (in 1982 dollars).
Front disc brakes annually prevent 10,000 accidents that would have resulted in 64 fatalities, 5,700 injuries and $32 million in property damage. They add $21 to the lifetime cost of a car.
There are millions of cars made today with drum brakes. They all stop fine.
