Late but i remember reading about this years ago. Ive tried it on the GMT800 but not on the '400s.
I still have that tank somewhere. but it worked good. I think it was an extra 17 or 18 gallons.
http://z71tahoe-suburban.com/iboard/index.php?showtopic=30390
I still have that tank somewhere. but it worked good. I think it was an extra 17 or 18 gallons.
http://z71tahoe-suburban.com/iboard/index.php?showtopic=30390