[V8Vairs] Cooling

[Jim Acker]

Denny made some excellent suggestions and I second each of them.  Before I would try any of the non-water based coolants, you will want to make sure you have all the major rust deposits out of the system.  These products are very expensive and should only be used after you have sorted out the cooling.  They can be used to get an additional 5-10 degrees of cooling, if needed.  SBC engines like to run around 200-210 degrees, so don't worry if you settle there.  I run a 180 thermostat with two 1/8" holes drilled 190 degrees apart (or you can buy them this way from a performance dealer like Speedway or Summit.  This allows some water movement before the t-stat opens and can help burp the system as well.

My own experience has tipped the scales to the importance of airflow management over everything else, assuming you have a good radiator and water pump.  Second, is ensuring you have all the air out of the system.  Burping the system with the front of the car in the air doesn't always do the trick.  Pre-LS SBC engines have a tendency to trap air bubbles in the back of the engine.  A good trick is to drill a tap in the back of your intake manifold above where the water jacket hole is covered by the manifold.  If you are careful, you can do this on the car.  Install a bleeder and use that to get the air out of the block.  A much easier solution is to simply remove the thermostat and hand-fill the engine with coolant with the nose of the car up in the air.  Then fill the radiator, ensuring you have the air bubbles out of the hoses and fill the overflow half way. Always put a bleeder on the top of your radiator and use it to bleed the last of the air out as the engine runs.  Do not open it until you feel the hot water coming into the radiator, as opening before that can actually introduce air into the system.

Back to the airflow.  First, you need to make sure the surface area of your intake opening is at least as large as your radiator surface area.  Second, you need to make sure your radiator and fan are well enclosed to ensure maximum efficiency. Not sure mouse holes need to be plugged, but you need to manage the air so it all goes through the radiator and then make sure you have the biggest fan or fan combination you can find.  Mine is a 16" Zirgo pulling 2400 cfm.  That is the best rated fan I could find at the time.  Last, you need to get rid of the air.  After lots of experimentation, I think Arch Evans got it right with the shark gills in your wheel wells.  I run these and they work great.  Simple and effective.  You create so much positive air pressure in the trunk that even rain water off the wheels can't get in.