I went to Mason Dixon in August this past year to race with the 422 guys as they have a group that runs with them called AMI racing. My brother has raced in the 422 classes with the 64 Max Wedge car he is driving and they let me race in the AMI classes since I dont have a crossram. The AMI run every 1/2 second as I had to run the 12.00 class since I ran 11.80's on the mountain in the heat. But I had a blast as they ran the .400 Pro tree in the AMI class I ran. I believe it stands for "All Motor Index" and it at least gives the guy like me who has a car that looks the part body wise but has no crossram setup a class to race in. I believe the 422 guys run on the tenth dail as my brother ran 10.70's at MD and dailed 10.80 running with the 422 guys. Ron