Having traveled down the same path you've taken with the short waterpump, trying to use the stock fan w/new radiator, getting only 3/4 of the cooling system capacity into the engine I would offer these suggestions:
1. The cooling system capacity is 16 quarts....give or take a little. Without a thermostat you should have been able to completely fill the system. With a thermostat in place you often have to"burp" the system to get it full. Without the thermostat you should have been able to fill it completely. No thermostat will allow the pump to circulate the water too quickly to effeciently cool the engine.
2. The short shaft pump pulley may not give you the correct pump speed which adds to the above problem. Overspeed of the pump can cause cavitation and result in overheating. Add to that a stock fan which is located low on the radiator and I could see where you could have problems.
3. The solution to ALL of my engine temperature control problems was relatively simple:
A. Using the ADAPTOR Plate and the early 216-235 water pump you achieve the correct pump speed and more importantly locate the pump in the center of the radiator.
B. Replace the stock fan with a 15" 5 blade fan such as the Flex-a-lite FLX-1615P (Summit@$24.95). You will need to open up the center hole to 1" to fit the 1" snout of the "early" style 216-235 pump. This can easily/carefully be done with a circle template, scribe, and a rat-tail file. In addition this eliminates all clearance issues with the harmonic balancer, A/C compressor, Alternator/generator, and power steering pulleys.
C. After you've added the adaptor plate/early pump setup, fill your engine block from the thermostat housing before you add the thermostat. This gives you a full block of coolant. I also drill a 1/8" hole in the thermostat rim to allow full refilling to "burp" the engine.
D. Make sure that your engine timing is fairly close, you'll want a 50/50 antifreeze mix, add a 4-7 psi cap, a 180 degree thermostat and your temperature issues will be a thing of the past.
E. Hang the "short-shaft" water pump up in your shop and enjoy driving your truck with NO CONCERN about OVERHEATING issues. In addition, you can purchase a replacement pump should you ever need it from your local auto parts supplier.
BTW....54 my truck is a daily driver, has A/C and never goes over the 180 thermostat temperature during normal driving. I've added pictures and documentation to my webshots albums of the ADAPTOR PLATE install. Click on the "Full Size" feature to read the instruction sheet on the adaptor plate. Do youself (and your truck) a favor and make the conversion and be able to enjoy driving.
Dave
Last edited by Fla54Chevy3100; 01/21/2008 3:03 PM.
