Hi I just rebuilt my sbc 350 engine I put the vortec heads on it and went with a mild cam comp cam 212 intake and exhaust and 440 lift on intake and exhaust. The problem is that it took out number 7 intake lobe less than a hundred miles. We put a new cam and lifter in it and broke the cam in and drove for 20 min. and it was acting funny. we took it apart and found out that number 7 exhaust lobe was gone. Does anyone have any ideas what is causing this.