speed is no measurement. The true test for a 1HD in your cruiser goes as follows.
get some 30,000 lbs proof rope, tie it to chassis rail. now find a telephone service pole and tie it around it (solid) - put in Low/Low and apply power to take up slack on rope - give it more juice (keep an eye on your surrounding for cops, idiots and also transmission, turbo and engine temperature) - If you can bend a small telecom pole - your 1HD is good.