Pegging is not good. I'd say 1600 cfm is not enough air movement. Go for more cfm's if possible. Check all the usual suspects, flush, therm opening as rated, 5-7 lb cap. Timing correct? Exhaust valves set with enough delay to transfer heat. Engines will overheat (creaps up) if the valves are not gapped enough to allow heat transfer to water gasget. Is you vacumn advance working? All these will contribute to an engine overheating.
