I have a 96 GT that has 231000 miles and smokes when first started.Engine running,no smoke at all.Still runs great,but I would like to try replacing the valve seals and see if that takes care of the problem.A full rebuild is out of the question right now due to budget issues.I have some knowledge of mechanics,but need advice on how to replace the seals,hopefully without taking off the heads.Any special tools required?