I am rebuilding a Chev 305 for my wife's 78 Camaro. I took apart the heat shield from the bottom of the Intake manifold to clean all the carbon out. My question is just exactly what is this on there for, and is it that important to put it back?

MalibuKid, I assume you mean the one on the underside of the manifold that's held by four rivets. It's designed to keep hot engine oil off the bottom of your intake and, therefore, keep the hot temps off the bottom of your intake.

yes, the bottom of the manifold gets hot where the exhaust crosses over and it will cook the oil that gets on it.
(edit) Gene you beat me by a whole minute I'm going to have to learn to type faster.

[This message has been edited by 64elcamino (edited 06-08-99).]

Let me add just a little something to the above. The heat shield is important and should be put back on only if your exhaust crossover is left open. The purpose of the exhaust crossover is to help vaporize the fuel before it gets to the cylinders when the engine is cold. Some people like to block the exhaust openings in the intake gaskets which prevents hot exhaust from passing through the bottom of the intake manifold. If you have this exhaust crossover blocked, then you would not need the heat shield.

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Thanks guys for your input. Putting this shield back on is not a problem, I am just wondering if these rivets ever work there way back out. Kind of like pulling a nail and driveing it back in the same whole. Maybe I will try blocking the exaust crossover like dzauto suggested. Thanks.

Does the 78 have the choke operator spring gizmo on the manifold? Blocking the heat will not let this work and you'll need a hand choke or something. If you have electric or something else, disregard my ramblings. tom