here is what i got. i slapped a camshaft in the stock 5.3 motor in my 05 suburban z71 flex fuel. i had a decent tune in it for over 2 years. ran decent. i built another stock 5.3ls to replace factory motor. only part that is different between the 2 motors is the valve springs. i went from stock to .600 in valve springs. now the tune i had in before engine swap wont alow motor to run correctly. wideband and vcm scanner show motor running to lean & i cant seem to get it away from being lean. any help would be great. DERICKS TUNE NEW MOTOR..hptDERRIK BURBAN NEW MOTOR FIRST DRIVE.hpl