Stock,
I you pull the rad cap with the engine cold and fire it up the flow should be evident. Cold rads, warm engine is a strong inidcator that you are not any getting flow. I recall one member who had the impeller spinning on the shaft. Rare but can happen I guess. The nylon pump drive gear could be a weak point, but then again after 14 years mine looked like new. I would suggest taking the water pump apart and inspecting. Also, definitely pop off the head and look at the piston crown. Its hard to tell from the pic but there appears to be some deposits on the plug, possibly aluminum. Cam.