I haven't heard of cam timing causing overheating problems but I guess it's possible. If you haven't done it before, it looks a little intimidating to check and/or adjust valve timing but if you get a good degreeing kit (Summit carries one for around $75) and a good instruction manual, it's not bad at all. It requires you to pull off the timing cover however so it's not just a 1/2 hour job. Your first time will probably take all day ....maybe two! Ignition timing is much more likely to cause overheating (along with dozens of other things). Usually from the timing being too retarded.