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Hi all
Have a question about the ZZP ported manifold.
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The ZZP manifold has welded coolant passage.
The stock not its open.
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Do I need this coolant passage or not?
If not its only an easy change and nothing more?

thanks for your answers
 

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This is a common leak point, and is only there to send a bit if coolant to the throttle body, so we tend to block it off when modding. It's meant to not let the throttle blade freeze open in you're doing a 5min wide-open run in sub-zero temps at the North Pole (exaggerating, but GM basically has to cover their behinds for various oddball cases). The TB is directly in contact with the s/c already, and temps are transferred through conduction already, in case you're wondering, just put a hand on it when warm for a second if curious.
 

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I am still of the opinion that when that passage is blocked off the end cap coolant bypass cap should be removed and a quarter inch thick 4.5 inch grinding wheel should be used to open up a quarter inch by quarter inch trough between the rear and front crank passages leading to the thermostat housing.
I do this to restore the coolant flow that GM calculated the Restriction to force coolant through the throttle body otherwise the fluid would remain stagnant.

I also caution against removing the factory paper gasket in favor of just RtV as the thickness of the gasket would change the area of the coolant to flow through
 

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True, I tend to forget about opening the side port a bit. It's pretty easy to do with a grinding bit on a Dremel, die grinder, drill, etc.

Not sure what you meant with the paper gasket... For the side cover? Notching back that center rib inside the side opening will more than make up for the minor difference in gasket thickness.
 
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