I have an exhaust leak on my 72 chevelle with 307. I took of the exhasut pipe today and it has a ball and socket joint, and no gasket or donut. Ive been told that there should be sometype of gasket but then others have told me that there are not gaskets?


Should there be a gasket?

google walker exhaust and find the lay out for the car. it will indicate if you need the donuts or not.

The need for an exhaust donut is 100% TOTALLY dependant on the shape of the outlet of the exhaust manifold that is on your engine.
The earlier manifolds used on Camaros and Chevelles DID USE a donut and a sleeve. The manifold outlet was beveled, thus requiring a donut. Later manifolds, with nearly an idential shape, had a kind of ball shape to the outlet (sounds as if this is what you have). This ball shape fits into the FLARED end of the exhaust pipe and is sealed when the 3-hole flange is pulled up tight against the outlet of the manifold. If this is what you have on your engine, THEN NO GASKET OR DONUT WAS USED. This change to the manifold outlet was made so that the donut/gasket could be eliminated. It was a relatively good idea, but frequently did not maintain such a good seal as the pipe/manifold got older, rusted and pitted.
I'm not 100% sure, but I didn't think the change to the ball shape at the outlet occured until sometime later than 1972.
But, if this is what you have, about all you can do it try to snug up the nuts on the manifold studs a little more. Be careful when tightening nuts on these old studs. They may have rusted together, becime thin, weak, and break off with minimal torque!

And fwiw, AMC used half a donut w/ a sleeve on their 258", 6-banger, not good at all imho b/c they had problems and ended up selling steel 1/2 donuts!!

pdq67

My 70 307 needed donuts, not sure about your year though. I reused the stock manifolds but took out the heat riser valve on mine so it is straight through. I know that most new style manifolds have the ball built in and the head pipe seats to it with no gasket or donut. A visual inspection of yours should do the trick, if your still not sure post a picture here and someone will confirm what you need.

Steve