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post #1 of (permalink) Old 01-07-2006, 07:57 PM
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chevy HO manifold water flow

Can anybody tell me the water flow thru this manifold. I need to figure out which port to enter and which to exit for the heater core supply and return?

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post #2 of (permalink) Old 01-08-2006, 12:28 AM
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Re: chevy HO manifold water flow

the port in the picture that is on the right, bottom side, will be one of your water ports. if you were looking at the motor it would be by cylinder #2. the other port will be found on the water pump. the threaded hole up by cylinder #1 is for the temp sensor.

if you put a line running from one side of the intake to the other, you don't gain anything. they are both on the same side of the pump, thus water does not flow.

the port toward the rear is for vacuum (break booster). the funny looking cut out by the carb is for an thermostatic choke. Holly Carbs use them. The other is for an EGR valve.
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post #3 of (permalink) Old 01-08-2006, 10:19 AM
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Re: chevy HO manifold water flow

Looks like a Performer RPM series manifold...

Not a good choice for off-roading. Off-roading requires lots of idle and low rpm operation, both of which Performer rob to pay for upper end rpm performance.
If you are doing mud bogging or something like that, it should be fine for your application.

As for heater hose line placement...
Heater feed should be on the water pump it's self. Look for it on the passenger side of the water pump.
Return should be the hole staring you in the face in the right front corner.
This one keeps the hoses as low in relationship to the block as possible.
You can always return to the radiator, if your radiator has a heater hose nipple.
Some heater hoses return to the top side of the thermostat housing.

Run either one of your heater hoses higher than the top radiator hose, and your heater will NOT work.

Here is another little tip for people working with raw cast aluminum...
Use Plumbers Dope and not tape when you insert the heater hose nipple.
DON'T OVER TIGHTEN! Let the Plumbers Dope do the work, 15 to 25 INCH POUNDS (NOT Foot Pounds!) is all you need to keep the nipple in place.
If you over tighten, you WILL crack the intake right through the water passage.

Use new bolts & washers of good quality under your intake bolts also. This will keep your bolts from cracking and distorting the intake flanges.

If at all possible, Before Installation, Heli-Coil the threaded bolt holes, like the carb mounting holes you are going to use, and the water neck holes.
Threads pull out of raw cast aluminum so easily, and raw aluminum seizes to steel bolt threads so very easily...
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post #4 of (permalink) Old 01-08-2006, 10:58 AM
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Re: chevy HO manifold water flow

Thanks for the post. The manifold is from the zz4 crate motor. My main problem is that i have a cast iron water pump with 2 heater hose nipples on it. So this is what is throwing me off in respect to routing the heater hoses to the core and back. The water pump is from a 1999 chevy tahoe 5.7 liter. I do relized that the preformer manifolds rob low end for high end but this setup has so much power thru out the range it is scary. thanks for your help
post #5 of (permalink) Old 01-08-2006, 08:27 PM
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Re: chevy HO manifold water flow

chevy guy here.

your best bet would be the standard chevy truck 4 bbl manifold. edelbrock's standard performer is the best all around manifold. don't go for totally open manifold, again you will be loosing low end.

also, don't go any bigger than 180 cc for the head runners.
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