Hi, Perry, just passing along some ST 60 info from the late Big Jim Greenaway. Jim's engines were set up with generally .312 restrictors, so the engine would use about 6 ounces of fuel. Jim believed that quantity was critical to allow proper cooling/cycling for the distinctive 4/2/4 "growl" of the old ST 60's. Dave Cook, on the other hand, had success with smaller restrictors, about .280-.285, using only about 5 ounces of fuel to do the pattern. Lots of opinions...Might want to check with Len Harding, as he has built/rebuilt lots of 60's and 46's over the years, to get his thoughts.