The Stovebolt Site Forums The Shop Area Engine Shop Correct donut exhaust gasket for 235 exhaust manifold to header pipe

I have another question, this time regarding the correct donut gasket on a 235 cid that goes between the exhaust manifold and the exhaust header pipe. I have tried several donuts and have had trouble sealing off the exhaust system at the joint. Does anyone have a solution? Looking at the old header pipe it seems like there might be remnants of something that looks similar to a rope gasket in the recess of the header pipe, probably made of asbestos. Anyway, I would be interested in hearing about solutions and possible workable part numbers for the stock exhaust on a 1955 235 engine. I thank you all in advance.

Usually the gasket you get with a full gasket set will do it fine, or you can purchase these separately from nearly anywhere. You know the exhaust pipe slides into the manifold and there's a lip on the exhaust pipe that mates with the exhaust manifold and a separate piece slides up and holds the donut seal in place, yes? Two threaded studs coming out of the manifold mate with this piece and it simply tightens up against the donut. Take a look at the image below. Hopefully it will be self-explanatory.

This one should work...https://www.rockauto.com/en/moreinfo.php?pk=11478469&cc=1487268&jsn=410

Jon, your link doesn’t work.

Drag your cursor through it, highlight it and then right click to get the option "go to...."
Sorry, but I have no control over the script the site is running. Sometimes links work and other times, they seem to go a bit wonky. Could be me, also or the way I put it into the sentence. Let's try this:

https://www.rockauto.com/en/moreinfo.php?pk=11478469&cc=1487268&jsn=410

I tried dragging and dropping but to no avail. That last one works.

My gasket on my ‘59 235 is different. It’s flat instead of the donut style. Although the manifold uses a donut style, the flat flange on the pipe does not. More that likely, the muffler shop used by a PO, used what they had on hand, instead of obtaining the proper flange. For now it doesn’t leak but I suspect it may have to be changed in the future.

Use the brass nuts also ,makes it easier when it has to come apart.

Interesting, Phil. That type of gasket isn't used anywhere on mine. I've seen those used plenty of times when mufflers or catalytic converters have been made so they can be removed by un-bolting, but not in AD trucks.

That donut is the standard part and I am using a Fel-Pro equivalent.

However, if you have a poor manifold to exhaust flange fit....there’s another FelPro (for a different application) with the same inside diameter but a larger OD and taller profile. The guys at my Napa store let me wander around in the back one time and we found this.

I’m lousy at documenting this kind of stuff, but if anyone is curious I will see if I retained the package that would have the part number.

My parts stores are not always that accommodating to let me check out their stock. If you do have a NAPA number, I would go and check it out.

Plug in your info and you can find any part you need for your vehicle. www.napaonline.com

That was what I removed during my recent engine rebuild. I tried the donut gasket that came with my Fel-Pro gasket set, and it would not mate against the flat face of the exhaust pipe. For now it works with no leaks, but I know it’s not right and I’ll address it one day.