I just purchased a 65 corvette convertible, 350 eng, 4 spd, holly 750 carb and side pipes. Why do I smell exhaust fumes all the time. Carb checked OK and replaced PVC. Can not find exhaust leak. Is this common and how do I fix.
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ANSWERS: 4
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uhmm it's a 1965 350, it could be on the rich side, but is most likely normal, I would however check for fuel leaks, sometimes when the fuel pumps fail the dump fuel into the crankcase, so check the smell of the oil
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Exhaust leaks can be hard to find. Try jacking the car up so that you can get under it. With the engine off, place a compressed air source into the tail pipe and seal it with duct tape and cloth. Then listen for air leaks and use your hands to find the leak. You may hear air leaking at the carburetor, that is normal as one intake valve will be open. Check around the header gasket too. A spray bottle of water and liquid soap will help find leaks that are hard to reach by hand. If the smell bad with the top and windows up then you probably also have an opening in the body or weather seals on the top or door are bad.
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Those side pipes might be leaking, especially if they are aftermarket items. Track down the leak using soap solution. +5
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This is probably going to be normal because to pipes exit just before the rear tires. It might be running rich too and it best thing to do is have a wideband O2 meter to measure the fuel ratio. Could be your floats are set too high or sticking, fuel mixture screws adjusted incorrectly, or you have too big of jets in it. I have a 79 Trans Am with a Demon 750 carb which is basically a Holley and my ratio was 10.9 at idle and 11.4 at a cruising speed. For my application with is just a standard carb and intake and no turbo or supercharger it should be around the 12.4 to 12.8 range. Too lean of a fuel mixture could create fumes. Usually it burns my eyes. Hope this helps.
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