Bypass hose for LA block with Magnum intake

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I'm talking about trimming some off the manifold nipple. MAD DART's manifold nipple is about half as long as mine, plus sits back about 1'2 further, so if I trim some off that nipple, or just get a shorter one, it should work
 
I would think it cools better without it?

so are we going with...the 2 larger w.p orifaces into the face of the block over power the bypass and that the bypass actually can intake excessive pressure from the manifold.

Or the latter?

It's pushing out all holes, bypass just eases the pumping psi?
 
here this explains it
"Thermostat Bypass System.— Reworking a small block's bypass system can pay off with improved cooling. Under normal circumstances, when an engine is cold, a bypass in the water pump housing allows coolant to circulate enough to avoid a pressure build up when the thermostat is closed, and to allow the thermostat to open properly. Some engine builders have found that improved cooling efficiency results when this bypass hole is plugged (with either silicone or a standard plug) and four holes are drilled in the thermostat. Typically, four 1/8" diameter holes are adequate. However, Myron Cottrell of TPI Specialties recommends four .200" holes in a 160 degree thermostat for summer operation and four .080" holes in a 180 degree thermostat for winter operation. This may seem like splitting hairs, but an engine that's overcooled produces less horsepower.The thermostat modification also improves block filling since air in the waterjackets has an escape path.

Even if everything in the cooling system is operating properly, drilling holes in the thermostat and plugging the internal bypass usually results in a measurable drop in cooling temperature. And it may cure an overheating problem if the "wrong" parts have been installed. Some race waterpumps and aftermarket cylinder heads ( a passage in the bypass circuit leads from the block to the heads) do not have provisions for the internal bypass.If the circuit is already blocked, the thermostat modification will cool things down."
 
1wild&crazyguy said:
I would think it cools better without it?

so are we going with...the 2 larger w.p orifaces into the face of the block over power the bypass and that the bypass actually can intake excessive pressure from the manifold.

Or the latter?

It's pushing out all holes, bypass just eases the pumping psi?
Click to expand...

The bypass allows some circulation when the thermostat is closed, so actually reduces pressure. Also, if the thermostat fails closed, you still get at least some flow.
 
The bypass kinda relieves the "shock" of cold cooolant coming in whne the Tstat opens, plus, keeps the engine at a more constant temp. Sorta kinda the same thing as the heater dumping into the lower radiator hose/pump suction like on the industrial engines and diesels. When the Tstat is full open, the bypass is just dead space.
 
And I disagree on the pressure, any pent up pressure can simply push out the bottom of the block, exactly what happens if it isn't purged properly, or overheats.

I'll run it because I have NEVER had an overheating issue that wasn't solved with timing.
 
Mine overheated because there were about 50 pinholes in the radiator. With the new radiator, I think it runs too cool (with the 318 that's currently in it).
 
64physhy said:
Just got a thought. Could I run a hose from the heater hose outlet on the water pump to the bypass inlet on the intake and cap off the bypass? It would still be getting that bypass coolant, just not as much. All I need is a 3/4" NPT fitting with a 5/8 "nipple, which I have found, and a piece of 5/8" hose with a 90 degree bend, which I have also found. I also have an NPT plug that's just the right size to plug the bypass outlet on the water pump. Sounds like a lot, but I think it's easier than trying to find a 1" hose with the right bend and twist to reach from the bypass.
Click to expand...

physhy....What kind of valve covers are those and where did you get them? Killler!
 
I got them from Mad Dart (Louis). I think he said he got them from Hughes. Not sure what brand they are. I've seen them on ebay before.
 
Well, I got it to fit. Had to cut 1/4" off the threaded end of the nipple and 1/2" off the nipple end and do some trimming to the hose, but I got it to fit. Not the "perfect" fit that I wanted, but it will work, and most won't notice.
 
I'm going to have to save for the Dyno. I just ordered a Dana, and will need a driveshaft, yoke, springs, etc. so that is setting me back some, but I see no reason to rush getting the engine in the car when the drivetrain wouldn't be able to put the power to the ground. I'll probably be ready to put the engine on the dyno in a month or 2.
 
I am running into this issue right now and is stalling the starting of my hot rod and cruising for the year. I have tried specialty hydraulic shops with hose that runs 60$/foot. The bend it needs to make is just too severe. Surprising that a Mopar supplier has not come up with a molded hose for these such applications. If/when I find the solution I will post it here and will advise what I did to resolve the issue.
 

64physhy ... I am in the same boat as you. I bought a BluePrint Engines 408 (360) from Summit that is an LA block with magnum intake and heads. I like you bought the molded bypass hose only to find that it gets severly kinked. Summit must know the correct hose as they show it in one of the stock photos for the 408. I will call them monday, but was hoping that you might be able to help me sooner.​


mll-bpc4085ctcd_dc_xl.jpg
 
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