Pertaining to the OPs original question, if he went with the Tow X or HP atmo only, what we be needed to make this work with the stock VGT (or a drop in 59 VGT)? Would it require your own fabricating?
A whole crap-load of custom parts. machined pedestal to accept a custom oil drain, custom oil supply, special down pipe flange if the turbo doesn't come from elite, same intake as the Jr. High Powers, custom turbo to turbo boost pipe with provisions for the fuel cooler. At that point, you just need to order the tow-x minus the vgt.
To the OP, if you're sticking with stock fuel and VGT, I think you'll be very happy with the 72. It's actually a 72.4mm. If I were on a fairly tight budget, I'd to a 72 and z-max jr. intake manifold. If you don't have an upgraded passenger IC pipe, that would come early on the priority list. Adding the vgt drops back pressure, and also adds power, as well as drops EGT's, so don't count it out. It's just a higher dollar item. When i ran the tow power plus compounds on stock fuel, it ran fantastic, and I really don't think there's hardly any more fuel to burn when running that combo. I also don't think think you'll be disappointed with the 76 by itself though, so take it for what it's worth. I do love mine, but I have the whole jr high power package. I guess my point is, that as amazing as the 76 is, I wouldn't plan on it unless I planned on the VGT as well. That's just personal preference based off of a lot of testing a lot of combos. Everything balances out better that way.
I wish I was still testing turbos, or had the means to do it up here in the oil field because I would love to test that 73 mentioned above. I tested a 75 cast wheel at one point, and it was pretty much on par with the 72, so it goes to show how wheel efficiency is a big deal, and smaller wheels can out-perform larger ones if the engineering is better.
