Yeah they do seem pretty simple, not into drilling jets though it's not just the hole size it's the flow, I've seen it go both ways on that something I learned many moons ago. Friend of mine had a Falcon drag car with Tunnelport 427 with 2 4's on it, one day at the track he was running kinda lean so he decided he was gonna try drilling jets so we did and it worked, two passes and the car went faster each time, but third time 3/4 track it was a melt down and holed two pistons was that ever a surprise, (at the time I didn't know that he already talked to someone about that and he was told you don't drill jets) so he took the jets and had them flowed and they flowed less then than in their original state before the first drilling, big learning curve there,LOL. I also learned that with my injectors not to mix different brands of pills, I had the same number pill from two different brands and they both flowed different.