working on a 77 dodge 4x4 with 30,000 miles on it , customer had some one install a edelbrock performer cam and lifters , and new pushrods ,an Intake and 4bbl now the engine has a tapping noise coming from vavetrain area that is intermitant, took vavle covers off everything looks fine, If it were mine I would have replaced rockers too. some times the noise seems to come from bellhousing area too, any suggestions what to look for would be appreciated