Even though I'm don't spend too much time at the track ( although I'd like to ) , I use a tach. I usually have a full exhaust under the car and sometimes have a hard time hearing my engine when staged next to a dragster of other really loud engine. Back when I had a 4 speed, the first time out, I nearly killed the engine because I think I dumped the clutch in my 440 roadrunner at what I would guess was around 1500-2000 rpm. The next time out was next to a green mustang pro-street, gave it some gas and burned the tires through the first 2 gears . Next run I taped a tack to the steering column..... was much faster on the 3rd pass That was over 20 years ago, now I'd like to get rid of the monster tach ...