There are several factors that will destroy your cylinders before even getting to the cruise part of the flight:
- the full rich mixture setting not being rich enough on take-off power and the subsequent power reduction on initial climb. This power reduction (commonly to 25"/2500rpm) closes the fuel enrichment valve and will drive the CHT even higher. During a steady climb at full throttle, the CHT should stabilize. If it increases, your full rich is not rich enough and the mechanic should be asked to set it richer.
- during the climb, power will start to fall due to density altitude increasing and gradual leaning can be started by observing the target EGT. Leaving it full rich will rob power.
- proper baffling is essential.