Go onto ebay and type in Ford Water Pump Pulley, There are several 2 groove pulleys for small block (260,289,302) Fords at less than $30.00. You will not have any cavitation issues unless you plan on turning 7000 rpm while driving. As I said earlier this is how the factory would deal with augmenting cooling on high performance or air conditioned cars.
It's a cheap modification that just may help your cooling issues.
If you measure your current water pump pulley and the pulley at the crankshaft you can figure out where you are now regarding water pump speed . if both pulleys are the same size you are 1 to 1 meaning the crank and the water pump are turning the same speed.
if the water pump pulley is larger than the crank pulley then your water pump is under driven. And if your water pump pulley is smaller than your crank pulley than your water pump is over driven. I generally set mine up to be over driven with good results.

Pete

Ford 289/302 engines had a couple of versions of double groove pulleys that were common. Holes match up.

This one may not be available any more but used to be found on the web. The front groove matches the typical Y-block pulley and its near a 10% speed increase.

All of these cavitation theorists need to take a look at the design of the y-block pump impellors. More likely to rust off than erode from overspeed!!!!!!!

 
 Steve Metzger       Tucson, Arizona

not mine! they were aluminum!

Frank/Rebop

Bristol, In ( by Elkhart) 

The Mota pulleys are available on Amazon.

For those that want to experiment without buying a shiny new pulley........... and Concours used to ask $100 for the speed increaser.



This is a 302 cid, 2 groove WP pulley with the rear groove cut off. The lower pulley on the small block Ford isn't much different than the Y-block so you are not exploring dangerous territory with the increased WP rpm.

To correct a minor amount of mis-alignment, the mounting flange on the WP can be shifted back or ahead with a puller or press.

 
 Steve Metzger       Tucson, Arizona

When I bought my 56 it have very few miles on it. The temp gauge drove me crazy so I started carrying my lazer pointer thermogun. First when it gauge was almost to the H mark the temp at the thermostat was 200, at the metal at the radiator top hose was 185 and the temp at the metal of the lower hose was 170. The gauge seemed to move continiously and drove me crazy. The first thing I did was buy a higher capacity radiator becaure I too want to add A/C some day. Actually saw very little change just took longer to heat up. It already had the big fan.

I came here to the site and started asking questions. Everyone was helpful especially Greenbird56. I replaced the themostat with a high flow 160 for a Mopar and put a plug in the bypass hose with only a 1/8" hole. All this helped a lot. Once the coolant temp was ALL really the same temp did the gauge calm down and stay pretty steady hovering just over 1/2 way. Temp was 170 at the thermo housing 165 at the top hose on the metal and 145 at the bottom. Green said if your going to idle around to go with the smaller pully which I haven't done.

One of the biggest change and last change was adding the metal and seal from the top of the radiator mounting and the hood. This forces almost all the air from the front of the car thru the radiator. I've kept with the 7 pound cap and some times the temp gauge will creep up and I'll see the thermostat open more or what seems more and the temp go down to 1/2 again. Moving always helps even at slow speeds. Good Luck

56 Vic, B'Ville 200 MPH Club Member, So Cal.

I think I have found the problem /stock pulley is 7 1/4 dia /this pulley is 6 inchs that's a lot of overdrive /does any one know if a 2 sleeve pulley from a 68-71 ford 390 will fit/ its a 7 1/4 pulley c8ae-8509-a

55 and 56 Fords had splash pans mounted under the front of the engine, these helped with cooling also.

if the bypas is restricted ther will be no flow when therm is closed,whentherm open very litle water flows threw bypass

This whole thing is easily demonstrated to yourself - put a 3 foot section of hose on the discharge of the bypass at the manifold and let it flow into the radiator cap opening. Plug the port on the water pump that it ordinarily connects to. Judge for yourself what happens when the thermostat is closed - and open.

 
 Steve Metzger       Tucson, Arizona