ET, hp, 0~60, the new models of G-Tech do it all. My 1st G-Tech used a single accelerometer and had to be mounted level with the suction cup. The new ones use 3 accelerometers, plus GPS and picks up your spark signal for rpm. With my 355 sbc I ran a 10.8 @ 132 at Sacramento Raceway, and that matched what the G-Tech told me. I also use it for cornering Gs. The 383 on the G-Tech was 11.4 which would be right because I built it for torque down low and gave up 66 hp on the high end. A couple of weeks ago I did a run with the newly installed 427, which has 206 more hp than the 383, and when your car weighs 1790 lbs, the addition of 200+ hp is quite a character changer, recording a 9.739 ET, I'm a happy camper.