You didn't say if you got those numbers by just doing a dry test or after a wet test. Try squirting some oil in the low cylinder (you should do all cylinders) and check it again. If the compression comes up more than a couple of lbs you could have a ring problem. Otherwise it is likely a valve problem and can be fixed without overhauling the entire engine. The rule of thumb is that more than a 10% variation between cylinders indicates a potential problem. As truckernix stated if it generally runs OK it's not a major issue for now.
Fred
Last edited by rfs56trk; 04/22/2010 4:05 PM.