Have 99 F350, 7.3 super duty dually. getting ready to haul heavy 5er. Need to upgrade stock rotors and pads to extra heavy duty drilled and slotted rotors, and pads. any suggestions on brand.

 

Don't get slotted or drilled rotors. Go with a quality pad, like Hawk or EBC (there are a few; do some searches) and Napa premium rotors. You will get the best bang for your buck that way! Also consider replacing the soft lines with braided stainless steel lines. It's on the to-do list for my truck and I've heard it makes a noticeable difference.

I have EBC pads and while they work great, they do produce a good amount of dust.

 

Slotted rotors are all you need, if you are worried about it.