I concur with what's been said here. The slush box can't hold more than that 60 HP range for sustained periods. Sure it will be able to do 100 HP upgrade but will shorten the life of every part involved by at least 75%.

The NV4500 and NV5600 are much different and will easily do the 100 HP upgrades but one must be careful about the clutch and then the rest of the drive line since parts for the New Venture stuff is tough to come by.

The newer trucks are different beasts and can do things a little better than our models.

 

i had just a set of rv injectors (40hp over) in my 99 and didnt last but 1,500 miles on it and had to drop a TC in it. it has held 350 plus for a couple weeks then back down to around 300. i know have a VB in it so its hard to say how much it will hold.

 

with just 56000 miles on the odometer and 15000 with the smarty i can make the tc shudder at anytime in overdrive guess it is time for a new tranny

 

The 01 Auto I had burnt up the trans with just the Comp on 2X5 and it only had 89K.

 

mine just turned over 100k and i only have the baby bully dog on mine and it will shutter in lock-up it will actually bounce the whole truck i was pullin my buddy's pontoon boat and it shuttered and felt like the front tires came up off the ground i looked out over the hood and it bounced like 4 inches. that was with o/d off and as soon as the t/c locked up it did it i let off and it was fine i guess its time for a new one and some new internals

 

i'd replace the tranny anyway mine started to go out around 120k miles. you'll like the after market ones way better, helps ya put that power to the ground