that was my first step, i called and talked to II, they are a great bunch of guys dont get me wrong, but i am tired of a single for one and especially this one. maybe it is just the combo on my truck, but it surges bad, egts are through the roof, i cant tow my atv, my crusing temps while locked are 1100. that is just to hot, i know i have a good bit of fuel but all these guys talking about how a single keeps their truck cool are full of it at least in my eyes. so twins are my only answer, i really hope they work as well for me as they do others. the subject of upgrading my charger got side tracked by trying to sell me something. my 66 is already sold, just need to finish my twins.