That's awesome. Now that I hit my goal... curiosity makes me think what I could do to hit 20 mpg.
good video, your results match exactly what I seen on race week and locally for the same speeds
My Beaumont at the same speed gets 18mpg steady with a 3.73 & 0.63OD . it is a 502 @ 4100lbs all in with driver. I run mine at 14.5-14.7 afr with about another 5 degrees of timing.
My old mans Camaro (3800lbs) with a LSA motor and TKO with 0.68OD overages 21mpg. 3.73 gearing. He runs the stock GM computer so its pretty well setup obviously.
Buddy Rich in red deer with the angry goat GTO gets 20-21mpg with a 517 Pontiac BB @ 4100lbs all in with driver, he has the 0.50OD gears in his t56.
my findings were as the speed went up, with the RPM, gas mileage dropped. When cruising at 85mph down south I was down to 12-13mpg, maybe even more. Ultimately gas mileage is driven by your RPMs, within reason or the confines of the motor. With the 3 examples above and yours included, HP is not the determining factor in MPG, efficiency and RPM is the driving factor. Obviously a full on race motor will not operate at 1800rpm and see the MPG.
I am toying with the idea of changing to a 0.50 OD gear in my T56 over the winter. Try and achieve +20mpg at highway speeds. my fear is that the motor will not cruise well at 1500rpm @ 70-75mph, well see how the new ZZ502 cam works... especially on boost!