Thank you for the reply. I plan to replace all the valves and re-assemble the engine. Is there anything else I should consider checking? Thank you for you help.

I recently had a friend replace an damaged exhaust valve. Unfortantley he did not properly inspect the timing belt system, the new belt fell of at idle. We removed the head to inspect the damage, many bent valves and small dents on the top of the pistons. I know I should replace all the valves but I...