Blocked water passages.

[Speedo]

Does anyone know the reason for the blocked water ports on the rear of the intake manifold?

Gus

 

[Amtek]

The intake manifold doesnt have provisions for water passages probably to keep the deck low for the distributor. First time I took the 350 apart I thought that was strange after just rebuilding a ford 390FE that has huge water passages all around. I suppose it isnt needed though as the cold water is pumped into the water block and pushed up into the heads and out towards the front. It would be a good idea to pick and scrape off all the scale that builds up in there if you have the heads apart.

 

[folkenheath]

Yes, from the factory the coolant flow is made to go in the block from the front, through the block, into the heads in the back, through the heads, out the intake in the front into the radiator. Yes, there are small ports in between there so water can flow out of the block between the cylinders, but for the most port you don't need lines coming out the back of the intake unless you are doing extended high RPM racing.

 

[Speedo]

The intake manifold doesnt have provisions for water passages probably to keep the deck low for the distributor. First time I took the 350 apart I thought that was strange after just rebuilding a ford 390FE that has huge water passages all around. I suppose it isnt needed though as the cold water is pumped into the water block and pushed up into the heads and out towards the front. It would be a good idea to pick and scrape off all the scale that builds up in there if you have the heads apart.

The engine that brought this question up is an '89 5.7, the intake has a full size water passage that has those passages blocked off by means of a piece of tin in the gasket. Some other gaskets that I've seen simply have no opening (save a small hole to eliminate air bubbles) cut for the rear water passage to allow for the free flow of water from one head to the other. It would make more sense to me if they had no passage in the intake manifold at all except that there is a fitting for the heater supply in the crossover passage in the manifold.

Gus

 

[Amtek]

The heater supply/bypass outlet is on the front of the engine near the thermostat and that passage should never be blocked. I've recently rebuilt the 350 in my truck and swapped between two edelbrock aluminum intake manifolds, both had no rear water passages built into them. However, the water passages on the intake gaskets were open on both the front and rear so it wouldnt matter what side they were put on.

I dont have much experience with chevy SBC's but both of my aluminum intake manfolds had no rear water passages at all, only in the front where the thermostat and other outlets are. If your intake manifold has water passages on the front and rear, then I dont see why it should be blocked the gasket. I have seen people block the EGR ports that way but never a water port.

 

[Speedo]

The heater supply/bypass outlet is on the front of the engine near the thermostat and that passage should never be blocked. I've recently rebuilt the 350 in my truck and swapped between two edelbrock aluminum intake manifolds, both had no rear water passages built into them. However, the water passages on the intake gaskets were open on both the front and rear so it wouldnt matter what side they were put on.

I dont have much experience with chevy SBC's but both of my aluminum intake manfolds had no rear water passages at all, only in the front where the thermostat and other outlets are. If your intake manifold has water passages on the front and rear, then I dont see why it should be blocked the gasket. I have seen people block the EGR ports that way but never a water port.

Heater supply is on the rear of the intake and the return is to the radiator, that is why I had a question, it just didn't make any sense to me.

Gus

 

[4xcrazy]

One style casting, either head will fit either side, otherwise they'd need two different casting processes. Cheaper the single route.