Rebuilt 1999 454 MAG MPI ( serial M00345) that only had 35 hours on it but has sat for a long time damaged by water. Went to fire it up for first time and it over heats quick. Raw water pump is new and plenty of water going out exhuast. However water in the block seems to be stagnant. Technically the circulation pump only has 35 hours but it is over 10 years old. I believe it is cavitating and is not strong enough to push the water through the block and fight the flow out the exhaust. Because all four hose and the thermostat share the dame housing I believe the water pressure from the raw water pump is holding back the flow from the thermostat. I pulled the circulation pump and ran water through all the passages in the block and flow does not seem to be blocked. So I think it is the circulation pump.
1) Anyone agree?
2) im trying to figure out how to use a high volume pump but none of the one I can find has the nipple at the top. They all have two ports that go 45 degrees. Anyone else running a high volume pump?
3) I picked up an aftermarket exhaust and it appears the water flow holes were drilled slightly bigger. Do you think this is also affecting the flow from the block because the water can easily pass to the exhaust less restricted versus having to fight its way through the block.
1) Anyone agree?
2) im trying to figure out how to use a high volume pump but none of the one I can find has the nipple at the top. They all have two ports that go 45 degrees. Anyone else running a high volume pump?
3) I picked up an aftermarket exhaust and it appears the water flow holes were drilled slightly bigger. Do you think this is also affecting the flow from the block because the water can easily pass to the exhaust less restricted versus having to fight its way through the block.
