318 2bbl intake manifold?

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RH62

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I picked one up at the local mopar show for 10 bucks but im not sure if its good or not. the sheet metal cover that goes under the center of the manifold looks like it might be bent a little and i see what looks like carbon coming out from around the edges. does this mean its cracked or what? it is the exhaust that goes thru the center port and up under the thermostat bucket right?
I guess that plate being bent could have let oil into it and it could be burned up oil... but im not sure.
 
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RH62 said:
I picked one up at the local mopar show for 10 bucks but im not sure if its good or not. the sheet metal cover that goes under the center of the manifold looks like it might be bent a little and i see what looks like carbon coming out from around the edges. does this mean its cracked or what? it is the exhaust that goes thru the center port and up under the thermostat bucket right?
I guess that plate being bent could have let oil into it and it could be burned up oil... but im not sure.
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You're correct...it's probably coked up oil thats flaking off the bottom of the exhaust crossover passage on the bottom of the intake. You can remove that tin plate, clean all the gunk out, and run it w/o the plate if you want.
 
Is there a way to block offf that passege, or is It necissary?
 
I took that plate off of a 340 4 brl manifold that I bought & it was packed with gunk. I am running an Edelbrock w/an electric choke so I do not need the manifold heat riser. I am however always struggling with vapor lock. Will leaving this plate off help or hurt my vapor lock situation? I would prefer to just leave it off so I do not have to worry about those little "studs" falling into the motor. If I leave it off do I have to block off that passage & if I should, what/how do I block it off? Thanks for any help guys.
 
The exhaust cross-over passage often gets carboned-up and the most practical way to clean it is to hot tank it. There is no way for oil under the intake manifold to get into the cross-over passage. The plate just keeps the oil in the lifter valley from splashing up onto the hot cross-over passage. If it's damaged, I would replace it.

I would also clean out the cross-over passage as it helps driveability for street-driven cars. If you block the cross-over passage to get a cold intake manifold, you will end up with an off-idle bog and will have to increase the accelerator pump shot to compensate. Leaving it functional improves driveability, engine life, and fuel economy.

If you have a problem with vapor-lock, the problem is that the fuel in carburetor is boiling in the carburetor. You can add more insulation (like another gasket) between the carb and the intake which will help. You can also reroute the fuel line away from the front of the engine to more directly over the valve cover. See SlantSix.Org Fuel Line Mod for more information.

Intake Manifold Heat
 
Thanks for info on the manifold. I am going to look into the fuel line idea. I already have a 1/2" wooden spacer under the carb but it is on a Holley aluminum Strip Dominator manifold & I am switching to a stock cast 340 manifold. I appreciate any advice.
 
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