track carb rule


New member
My smalltown track is thinking about adopting a 615. Carb rule with a certain jet. Everything else would be legal as long as it is a clone motor. My question is will this nullify modifactions to the motors? Or will the changes to the motors still be worthwhile? I know the carb and airflow make a huge difference, but how big? Any changes that will help me the most with this lone rule?
I can’t see them making the jet a fixed thing. Air density changes, this calls for more, or less, fuel. If the air density goes up, like in the cold winter air, you need a bigger jet. Not going to a bigger jet could hurt the engine.
Another thing is that all jets do not flow the same, even in the same size. Trust me.
This means on a hot day, those that have jets that flow the leasr could have an advantage.
And if the truth be known, leaving everything else open is ten times more likely to let some people go faster than the rest.

Comments, Complements, Criticisms and Questions are always welcome.
can't argue with facts! carb rule is good, but to get that far into the weeds on the jets is asking for trouble!
Most tracks in my area have a .615 carb rule, and jet 41 no go rule . No problems at all biggest jet we run is a 39. JMO