[Joel Koontz]

I recently bought a set of 72 cc Eheads for use on a street 455. Because of the compression I want to make sure I am getting the best possible coolant flow thru the heads.

How does the coolant circulate in a Pontiac V8? Is it simply pumped into the front of the block and then runs thru the block into the heads, then to the intake crossover into the radiator and back to the water pump? Is there anything that keeps the coolant from just going into the block and then directly thru JUST the front part of the heads into the intake crossover? What makes the water flow thru all parts of the block and heads?

The Eheads have less coolant holes(compared to several sets of stock heads that I have) but they have an "extra" coolant hole between the center two exhaust valves. The block does not have a hole to match the "extra" hole but the FelPro 1016 gasket does. Should I drill a hole in the block to match the hole in the head/gasket? Should I drill any other holes in the Eheads to match the "stock coolant holes" in the block and gasket? If so, where? I have seen suggestions that I reduce the size of the coolant holes in the Eheads or the block. Is this a good thing to do? If so, how, which ones and how much? Is there anything else I can do to get optimal coolant flow thru the heads?

Thanks, Joel

[Joel Koontz]

I recently bought a set of 72 cc Eheads for use on a street 455. Because of the compression I want to make sure I am getting the best possible coolant flow thru the heads.

How does the coolant circulate in a Pontiac V8? Is it simply pumped into the front of the block and then runs thru the block into the heads, then to the intake crossover into the radiator and back to the water pump? Is there anything that keeps the coolant from just going into the block and then directly thru JUST the front part of the heads into the intake crossover? What makes the water flow thru all parts of the block and heads?

The Eheads have less coolant holes(compared to several sets of stock heads that I have) but they have an "extra" coolant hole between the center two exhaust valves. The block does not have a hole to match the "extra" hole but the FelPro 1016 gasket does. Should I drill a hole in the block to match the hole in the head/gasket? Should I drill any other holes in the Eheads to match the "stock coolant holes" in the block and gasket? If so, where? I have seen suggestions that I reduce the size of the coolant holes in the Eheads or the block. Is this a good thing to do? If so, how, which ones and how much? Is there anything else I can do to get optimal coolant flow thru the heads?

Thanks, Joel

[Tom Vaught]

This is a very tricky question.
When the factory designs heads they do cooling studies to determine the optimal flow speed of the pump and water flow through the system.
They then instrument the engine and measure with
Thermo-couples (heat sensors) what the water temp
and surface temp is on different parts of the block and heads are. They then adjust the coolant flow holes to meet these cooling requirements.
They try and not have any hot cylinders.
In reality the design engineers can only do so much with their testing and in many cases have to rely on historical data.
The gasket manufacturers normally supply a gasket
for the engine when the engine is designed or if
a cooling problem is identified. This is a simple way to fine tune the hole sizes to fix a cooling
issue on the engine.
The "E" heads cooling holes were drilled into the
heads to fix known cooling issues on the two exhaust ports on the center cylinders of the block
and heads. The Fel-Pro gaskets also have revised
cooling hole sizes and positions.
I personally would not mess with the cooling holes unless I was plugging all of them for a
high boost blower application. Tom V.

[Joel Koontz]

Tom, thanks for the reply. Are you suggesting that I should not drill a hole in the block to match the hole in the Eheads/gasket? I understood your reply to mean you would not block or modify the holes in the Eheads but I was not sure about the hole in the block.

Thanks, Joel

[Half-Inch Stud]

The PMD engineers certainly design the cooling passages to eliminate hotspots, and promote uniform warm-up.

I continue to wonder about Pushing collant throught the head only. Using a fully water-blocked head gasket. And seeing if the Block can handle Street/Strip operation without overheat.

I trust the factory found the warm cylinders to beneficialy for power....but the uncooled block would be warmer RIGHT? So, my point is made.

These days, seems the Piston, rings, cylinder, and oil can handle a warmer cylinderwall. Most high-tech engine R&Ds are looking at ultra-high running temperature for more power and efficiency.

The risk reward is slight for us regular folks. So the Octane requirement is my key wildcard, showing that it is not worth keeping the water out of the block.

Oops, time for more coffee.

H.I. Stud

[PONTIAC DUDE]

[ May 03, 2002, 12:37 PM: Message edited by: PONTIAC DUDE ]