Spooky,
Welcome to the group. I only have about 200 miles on my Roush 511 8 stack so far. I did one tankfull of 110 octane(that motor loves it) and 1 tankful of 93 octane. It gets better mileage obviously on the 93 wihtout too much of a loss of power but that motor absolutely sings with 110 octane. Did Anthem build your car or did you do it yourself? I have went through a couple of tankfuls so far and I can tell you that on the freeway in 5th gear I am about 2000 rpms(loafing) and it was about 15mpg. driving it the way I do to enjoy that 511 and it was 7-10 but I will take that any day to get the grin on my face that the motor causes!!
