Don't know about the B/blk on gas, but down here or around Memphis where the humidity is always relatively high, they seem to run better on alcohol with the EGT around 1050/1100 degrees, which is sometimes hard to do from day to nite because the humidity goes up at nite. Heck sometimes the races don't get over until 1:00/2:00am, at the same track openened at 4:00pm for testing runs. With 2 buybacks and 50 to 70 cars in S/P it can be a long nite.
JMO
Zip.