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Passage cover = Front deck water passage?

if so...I would think the block would warm up sooner since you're splitting the cool water flow by diverting directly to the heads?

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the larger ones at each end of the block that go up into the head casting and then on to the intake manifold passage in the front and usually covered over in the rear by the manifold, thats where you drill/tap for the transfer tubes/hoses that go back to the thermo housing, so I drill a 1/2 hole in the head gasket to allow water to pass thru the normally covered passage, don't ask me how but it works real well,,,also the block is half filled if that matters.

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You make valid points on the bleeders, I have threatened to put those in after having some issues getting all the air out,, as far as the passages, this is somthing that looked like would be a cooling improvement,,does it work? well it dont run hot,never had the temp guage go over 180* at any time during a pass or sitting idleing in the pit's could it work better? possibly, if I had plenty of time and money then we could make an experiment out of this.

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could be as effective to just drill tap AN fittings in the rear and use them as bleeders, just cap them when it spills over...or tee them together and use a single tee.

Something else not talked about is we also used to run one of those prestone flush and fill tees in the (bypassed) heater loop so we could force feed cool (obviously not cold) water to the motor between rounds and spill hot water out of the radiator petcock.

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Dartman,

Yeah, the front (normally blocked off) is what I was talking about, I've been doing it and it works real well for me but I suppose opinions vary. The Aluminum heads are a huge heat soak so it seems if you keep them as cool as possible the deck surface can also wick some heat out of the block when the motor is not under load.

2 schools of thought about the rear, I think the best way to run the lines is to have a coupling that has a bleeder screw in it (like most modern cooling systems have). The reason is since it's still a closed but pressurized system, air can still find pockets in any high spots of the system. The bleeder screw allows you to purge any remaining air in the high spots. But if the system is completely purged of air the value of the rear transfer lines may be negated somewhat.

I want to do it on my 414 but the Victor 340 has that PITA cast in "tower" on the pass side and I'm too lazy to grind it all off.

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Jim, What you said makes a lot of sense and I've always considered that... some of the pump discharge will recirc directly through the radiator again, particularly at high flow rates and that could result in a cooler radiator and a hotter motor. however, as Stanton correctly mentions that a presurrized fluid will take the path of least resistence so limiting the size to 1/2" diameter or less (i believe) seems to still force most of the water through the block. A 1" Diameter hole (at the pump discharge intot he block) is 4 times the area of a 1/2" diameter hole in the head gasket. Also there are several other parallel paths between the block and the head, by adding one additional orifice you are proportionally reducing the flow across the other holes (and I suppose a block filled with fluid has it's own backpressure 'resistences') as well as the one you've added (for a given pump discharge rate). there are also the 'cast in" flow restrictions in each parralel path that come into play as well.

Like I said, it's all open for discussion, I've just seen some 'effect' benefits for keeping a motor cool between rounds

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I understand.....but when I was putting mine together.... I asked myself why would I even want to open a hole there? It would act like a tiny bypass of cooled water to come in and go directly out....The only thing it would do is slow down the flow to the other passages...I guess if you are pushing water through the motor to fast this would help...( I actually drilled my cometics and thought they were wrong)Sure you would still get flow through all of the other passages but it would slow it down...

I wanted to make sure my heads were cooled because I have heard of these old W2's cracking.. So after rethinking everything I blocked the front and reduced the top hole in the rear...
Most of the water in a stock system goes straight towards that rear top hole and pushes water through the top of the head out the front....Now I believe my heads are getting cooled more equally.. Forcing the water from the bottom of the head up and out...

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Crizilla,

think about this a minute and tell me if it makes sense.

If you seal an aluminum head with a copper head gasket you should have very good thermal transfer in both directions so where it's overly hot (like the bottom of head between those center EE exhausts) the heat should spread (dissipate) more effectively (compared to a composite gasket) between the thick deck surfaces of the block and head. So anything you can do to cool the heads more effectively should be beneficial to the entire system because (particularly and aluminum head) can act as a more efficient heat sink (when the motor is not under load).

Something a lot of people don't seem to understand fully about cooling systems is you can achieve lower cylider head and engine surface temps AND register hotter coolant temperatures simultaneously; Surfactants (such as water wetter....and Woolite, btw ) are designed to break down the surface tension of the wet metal and allow more efficient heat transfer FROM the metal TO the coolant system. The coolant temp rise can be a measure of it's effectiveness, however if it wicks more heat out of the motor than the radiatior can handle the coolant temp at the gauge can also rise. Watter wetter is IMO at least semi-misunderstood as to what it is really meant to do. you can see lower head and coolant temps...as long as the entire cooling system (fins, tube capacity, fans and of course the ambient air!!) is efficient enough to dissipate it.

Radiator (heat exchanger) effectiveness alone can be checked by measuring the Differential temps at the inlet and outlet.

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Agree on the first part - gaskets, and if you don't / can't run copper, MLS is the next best thing for heat transfer. Don't necessarily agree on the second part. It all depends on where you are taking the temp readings. If you are reading near the thermostat housing where most the coolant is converging before exiting to the rad, when that temp goes up, something ( and most likely everything ) in the motor is running hotter. It's why the factory puts it there. It is an "average" reading. The hottest spots in the engine will always be near the exhaust valves and the "twins" will be the worst. Obvious issues that many on this thread already know and are addressing. Some good reading on this (page 106) in the "How to build a big inch small block" mag by Jim Szilagyi. The chaptor seems to address the problem a little more directly by plumbing directly from the water pump to the center freeze plug in the block ( directly under 3-5 and 4-6 exhaust valves. The race water pump ( P4876548 )Is set up for this. Gotta use race cover #P4876632 with it. BTW, don't agree on the theory that the coolant travels too fast to transfer heat - not the same as regulating flow go give more to the hot spots.