overheat only over 3000 rpm

Newbomb Turk said

Are you running vacuum advance? If you are not, you need to be.

If it was overheating prior to the electric fans then my best guess is the pump isn’t turning fast enough.

I always suggest a Stewart Component high flow thermostat. And a high flow water pump.

But none of that stuff does any good if the pump is turning too slow.

If I understand you correctly you are saying it’s getting hot now at a cruise. That can easily be tuning.

If prior to that it was getting hot at idle and in traffic that’s a different issue.

It sounds like you have multiple issues going on.

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Thanks for your kind reply.

1) yes of course I have the vacuum advance. the correct one for the power pak, which is 13 degree advance. It works very well.

2) A high flow thermostat will be my next move for sure.

3) I have the feeling that for a 318 A poly there isn't any choice of water pumps.

4) When taking off the return hose from the engine, The flow of the water just slightly off idle is really abundant.

5) as I wrote earlier, after all the cleaning I did , I still have to check the behaviour on the highway,

6) Hot in traffic is a thing of the past now with the 4 fans setup.

I have the feeling that I am close to the solution, as I discovered that the coolant feed hose was squeezed in one of its bends before the pump and maybe didn't let the full flow of the coolant to get to the pump ....
The reason for that is because it was a little longer than the stock one, therefore at the very back of it there was a sharp bend reducing the flow.!

and no, I haven't got a spring in the hose..... I neve r had it.....