As an FYI - there are certain 'basics' to look at before doing a lot of other troubleshooing here.
1. CHT - it's generally recognised that the baffling directly behind the #3 cyl needs to be stepped of the head are (to give a gap for the air) a search will find the answer.
2. EGT - one simple check is to see what the fuel flow is at max power takeoff (adjusted for or at sea level) it should be approx 13.5 gals for 160hp & approx 16 gals for 180hp engines - mine was 10gal/hr (160hp) until I found out what it needed to be, that caused higher CHT'S in climb. Being a carby version the needle needed to be a different size, on fuel injected engines the fuel control unit needs 'adjusting' by a shop. (my big mistake was thinking that the Lycoming factory new engine was just a drop in item - works for certified airframes but not for homebuilts as the baffling & air intake systems can be/are totally different & resulting in different airflows).
Once the above is sorted then if you still experience high temps you need to look further as to the cause.