Im not sure yet. Iv only had it a couple of weeks and only ran half a tank through it. And that was with the EGR clogged up and gas smells like crazy. So im pretty sure I wasnt getting the MPG it is supposed to.

But, so far I have had some of the EGR problems fixed, and once I get the code 32 gone for good, ill be able to measure mpg.

The shift points arnt all THAT high, but they are compared to my truck (obviously). My truck will stay in 3rd gear all the way down to 5mph if it has to.

I get 18mpg on the highway with my truck (3.42 gears, 4L60E tranny, TBI 350, p275/60/15 tires). It turns about 2100 rpm at 70mph. I havnt driven too much on the highway in the Z28, but it seems to be near 2200-2300 at 70mph. Im assuming because of the smaller tire/wheel height (even though it has 3.23 gears).

Id love to swap out the gears in my truck and car. The Z28 with 3.42 would be nice... and the truck with 3.23 would help out on the highway. Like I said up above, the truck upshifts really soon, and if I could just get some smaller gears in it, that might help out a little bit (naturally it will shift at the same RPM, but will get me a little bit more speed before it shifts).

It needs better mpg on the highway anyways. I used to have a hard flushmount bedcover on it, and got about 20mpg. The bedcover got jacked up and I had to take it off, so Im back down to 18. (used to get 16mpg before the MSD 6a and flex electric fans).