I`ve got my eng in shop for rebuild,wipedout mains w/ bad detonation.I thought I had it under control,but I didnt.What do you guys use to keep an eye on things .I`ve heard of a scan tool called LM2.It`ll read air/fuel ratio and show it to you on its own screen and at what ever RPM youre going,,a little pricey at $350,but if it works! I have a scan master now,but not very good at understanding exactly what its telling me,but I`ll just have to get better so I can tune this thing better ---let me know what scan tools you use and what you think of em---thanks,,Jack