This is an interesting one

The new motor im building is a 347, 185 afr etc. Question is with the new horse power pulleys should I go with a high flow water pump instead of a standard one. I have read both side of the argument. One that it would help, and the other being that if I go with a high flow water pump the water does not spend as much time going through the radiator thus not cooling the water down as much.

What are your guys thoughts?

Radiator is a chinese Aluminum Rad with electric Fan. Radiator is also the same size as the 68 mustang. I cut up the 65 to allow for the bigger rad.

 

id go high flow............. the water wont get as hot i wouldnt think

 

I run a high flow and UDP's and have 0 cooling issues.

 

I have a high flow water pump with under drive pulleys. First time out I blew the heater core. Second time out I blew the gasket out the bottom of the water pump plate. Now the same gasket is leaking out the bottom between the plate and the water pump. If you decide to go that route use a cap under 10 psi.

 

Why would you use a underdrive pulley and a high flow pump? The idea of a underdrive pulley is to underdrive the accessories. The idea of a high flow pump is to overdrive the water pump. The two would appear to cancel each other out. I guess you would have normal or close to normal water pump flow but underdrive the alt, ac, and ps. Seams like a lot of work for not much gain.

I would think a high flow pump that is really flowing high would create more pressure. You would need to run a higher cap or the cap will just blow coolant and make sure your heater and radiator core can handle the pressure.

 

i have heard the discussion a few times that quicker flowing water will not cool.
i personally believe it's horsecrap (sorry my english), but I cannot prove it.
it will be one of those discussion going on forever. For any point that someone might make on that I have a theory that throws it apart. Unless someone proves that a highflow pump is not that good cooling I am not gonna believe in that

 

The reason I chose those pulleys is because I wanted that particular March Pulley system. I didn't know the water pump was high flow until after my first mishap. In the past I had never had problems with psi with any of my mustangs. Live and learn. I am now driving around with my cap not fully seated and have no problems. I just have not remembered to buy a lower psi cap. I have a overflow tank that stays at the same level. I don't fill my radiator all the way to the top either. I keep it about 1" above the core. I guess it helps that my engine never gets over 180 degrees even if I sit at idle for an extended period of time.

 

High flow pumps have larger impeller volumes. They displace more coolant turning at the same speed. It makes a bigger difference on aftermarket heads with better cooling passage designs that aren't as restrictive, or stock heads with a good cooling passage design.

 

That is exactly the idea. You would want them to cancel out. using udp would slow down your water pump so if you use the high flow you could get your water flow back but still gain the hp from the udp.