I bought a intake/exhaust gasket kit for my late 50s 235 and it came with a flat gasket and a donut gasket. which one do i use? they dont appear to work together and the shop manual was no help. There was nothing there when i got the truck so the swap and replace method didnt help me here.
Use the donut gasket if you're talking about connecting the exhaust pipe to the exhaust manifold. The inside diameter of the donut should measure 1 7/8 inches for a stock application. Ken
This may clear up the terminology a bit. The pipe from the cast iron exhaust manifold to the muffler is called an exhaust pipe and the pipe from the muffler to the back bumper is called a tail pipe. I'm sure your trying to connect the exhaust pipe to the exhaust manifold. Use the donut gaskest as it allows for differences in angle of the pipe to the manifold. I use a short piece of pipe that press fits inside the donut and extends up into the exhaust manifold when installed. It keeps the pipe flange and gasket centered to the manifold outlet and was a factory item on many cars and trucks. The donut will usually seal to even a flat flange and outlet but I usually bevel them with a Dremel tool to give a better sealing area.
Oops, I was meant to bevel the outlet hole on the manifold and around the inside of the hole in the flat exhaust flange, not the gasket.
