They kit the nail on the head. Steel thickness plays a HUGE role in heat dissapation. I use thin Borg Warner Hi-Energy clutches and THICK steels. I use thinner clutches to fit more in there. A brake pad thats 1.0" thick does not stop a car better then a pad thats 0.75" thick, because the surface area is the same. Clutches are the same way. We need lots of friction surface area and thick steels in between to radiate the heat away.

Also want to make sure you get correct line rise and volume to the clutch pack.

 

Stay away from the 9 clutch packs. They are a joke. 4000 miles and I toasted a set. I went with the 5 clutch pack Borg Warners. RockOn transmission uses the stock BorgWarner 4L65E clutches in their buildups and his transmission have been in 1000+ hp drag cars. One of his suggestions is a vacuum modulator in the transmission to regulate the fluid pressure instead of the electronic controller.

 

I upgraded to the Zpak and the wider Kevlar band. Also added a 2500 stall and the truck shift and runs like a champ.

Chris