Neither one, More pressure just raises the boiling point. It does not drop the running temp. If you have a stock heater core keep in mind it was only designed for about 7 pounds.

Don R.??

 

Yes it’s me…not a stock heater core

 

Here we go with the talk about the stock heater core only being good for 7 psi. Using that logic the stock radiator is only good for 7 psi also, but that’s usually forgotten.



Actually a heater core of the same construction and working condition should have a higher pressure rating than a similar radiator.

 

Consider a shroud if you don't have one. An aftermarket 7 blade fan as well as a spacer to move the fan closer to the rad. A higher pressure rad cap won't help your issue at all, as stated earlier

Larry.

 

A higher pressure radiator cap raises the temperature at which your cooling system loses it by boiling over.
If the operating temperature equilibrium is in the temperature range passed over by increasing the boiling point, then you still have a marginally effective or overwhelmed cooling system.
So it would be a band aid, and not a solution.

 

If you have a good shroud, the fan blades should be half in and half out if the shroud. It doesn't need to be close to the radiator. Stock or larger radiator? Show a picture of your system.

If you have a good shroud, the fan blades should be half in and half out if the shroud. It doesn't need to be close to the radiator. Stock or larger radiator? Show a picture of your system.

72 Monte Carlo 3 row cross flow radiator

 

It doesn’t look like your fan is half in/half out of shroud. Get a smaller (or eliminate) fan spacer to get there

 

And try it with the electric fan turned off at highway speed. Often times, the fan will slow air movement more when it's running than when it's turned off. The fan blades will turn faster when it free wheels and allow more air through it at high way speed.

 

I don't much like the louvered side panels. This allows air to bypass the radiator. I agree about the location of the fan. it needs to be brought back
some, unless the blades will hit something. Always a trade off.

 

That looks like a flex fan. But that will not be issue at speed.

Main issue is the louvers on side of core support as mentioned. You wan 100% of air going through the radiator.

Also as Don (Acardon) mentioned the pusher needs to be off at speed. If not that is slowing the air potently.

I would card board off those louvers. And try it. Make sure they are sealed. Not major issue but easy to see.


Main issue I see is a giant fan sitting right in the way of the air flow. Ditch it and the flex fan and you should maybe gain little more cooling. But at 205-210 you are not going to gain much maybe 10*.

 

remove fwd. fan it is blocking airflow at speed.
cover louvers on filler panels. you want 100% of the air forced thru the radiator.
get thinner fan spacer fan is 100 percent in shroud needs to be 1/2 in 1/2 out to flow properly.
one other issue I see is the shroud itself. looks like it's too close to the rad core causing an impedance in air flow where the big broad flat sides are. to be effective it needs to be at least 2.5" away from the core, otherwise static pressure will build inside stopping air flow in that area.

 

one other issue I see is the shroud itself. looks like it's too close to the rad core causing an impedance in air flow where the big broad flat sides are. to be effective it needs to be at least 2.5" away from the core, otherwise static pressure will build inside stopping air flow in that area.

This is a good point. That can slow flow through core.

Also one can cut holes in the flat areas and run rubber flaps so at speed air blow through and be sucked close stopped or low speed.

 

I don't think that's a flex fan. It is a riveted blade fan, but the blades appear to be fixed, not flex type. Not sure that small pusher fan is moving much air? I'd be surprised if it's more than around 2000 cfm or so. And being spaced off the core it's probably being deflected mostly and not helping much. Most electric fans don't put out whatever cfm the sellers rate them at, so need to go as large as you can find in both diameter and cfm.
I run a mechanical fan with no shroud, and a pusher on a thermostat controlled relay that comes on at 180 degrees. My car was at 185 yesterday with 97 degree ambient temp and idling in traffic.

 

unless the picture is reversed.......the engine fan is on backwards or is designed for a reversed rotation setup plus the electric fan almost serving no function at all, if you held a decent lighter a couple inches behind the rad it may blow it out but i doubt it.
Your main issue is the engine fan pushing air instead of pulling it.

 

unless the picture is reversed.......the engine fan is on backwards or is designed for a reversed rotation setup

I don't get it. Do you mean the fan mounted on the water pump in the third picture of Post #13?
SBC engine crankshafts rotate clockwise when viewed from the front, the same as the water pump pulley and fan.
The fan blades are canted in the same direction as a stock fan blade, so it will pull air through the radiator.
Am I missing something?

And none of the three pictures is reversed. They have text in each picture:. license plate, Vietnam sticker on the battery, and a Gates fan belt.

 

It pitched same as GM pitched the 4 blade fans.

 

Ok my mistake, sorry for the confusion