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On the tire size/final ratio , I was thinking that i would probably to a 37" tire or so based on what I've read so far on the 4BT RPM sweet spot for fuel mileage being around 1800, and fuel mileage really starting to drop off at any thing over 2000 RPM's.(hopefully for your sake you wont be stuck behind me when I take the maiden voyage this coming weekend if the thing only tops out at 70). Lol.....

Thanks for the suggestion on the Isspro pyrometer, I'll look for one. Do you by chance if the 4BT has a plug in the manifold for the probe ?
My truck will not go over 65 with excessive EGTs. (Unless down hill) My rpm is 2400 at 65. I generally cruise at 62 with EGTs of a 1000. My mpg is around 14-15. (Truck shaped like a brick.) So high rpms is not that bad for mileage, but I would be worried about hitting a long hill without a EGT. It is real easy to hit high numbers on a hill.

There is no stock plug for EGT that I know of. Hopefully, they already installed one.
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