Not sure what Ox66 actual fuel burn rate was, but to go along with other performance numbers I referenced above, it burns about 7 gallons per hour at 4k.
Tough to do an apples-to-apples comparison of actual use - I do keep track of gallons per engine hour, but find I am much more likely to keep the Suzuki running while I am fishing / drifting because it is so quiet, no smoke and sips gas.
-- Tom