Okay. I have been taking parts here and there that don't require machine work, cleaning them up and painting them for my 1966 Olds Starfire. I'm running out of stuff that is going to be red. So today I was cleaning up the exhaust manifolds and I discovered on the driver's side, where the donut goes, the "lip"? that it sits on is almost gone. It LOOKS like it is a steel sleeve inside the opening in the cast iron. Amirite? Where do I get this insert?

 

Yes it uses a donut with metal ring that inserts into the manifold. new ones can be had at your local NAPA and the like. There are different sizes so be sure on the diameter.

 

FelPro P/N 60421, under $6 at RockAuto.

 

Glad i found this thread! I had exhaust leak and it turned out to be both gaskets were bad on my 67 olds 88 425 4bbl. When i disconnected the crossover from the manifolds there was no gasket material. I had already purchased the new gaskets (donut) felpro 60421 but the ring didn't fit INSIDE the manifold. The mechanic said the ring went on the outside which didn't make any sense to me. It was a nightmare to begin with because the bolts broke off and had to be drilled out and now after 6 hours the exhaust still isn't fixed. I've looked at specs over and over and dont' find any other size (donut) relating to that year. Any thoughts??

 

If I remember correctly the crossover pipe is flared and there are NO gaskets for that. It is just a metal to metal seal. The manifolds have the outward bevel. Perhaps this is damaged on your manifolds? Some pictures will help here. The outlet on the passenger side manifold takes the donut type gasket with the tin collar that inserts into the manifold.

 

That's what i suspected because as i said there was no leftover gasket debris. I might add that this wasn't an easy task..3 of the 4 bolts broke off when trying to remove the crossover thus having to drill them out. The exhaust manifold gaskets were already replace and it was during another visit to the mechanic that the leak at the crossover occured. I suspect something shifted or caused the leak when he gunned it and squealed the tires to "test" the power, not once but 3 times. I did take a couple photos when it was in the air, not sure if they are any help. I'm going to give another shot at fixing it over the weekend, i will try and take better pics now that i know what needs to be looked at.

 

The picts are not great, need a better side shot, not straight on but the second pict, the manifold with out heat riser flapper looks to be damaged on the bevel.... or part of it missing as it broke off.

 

Oddly enough, that's not the side that has the exhaust leak. For some reason i can't get the crossover to sit dead center on the manifolds, almost as if the flares are bent outward on the one side. Leak occured after somebody took it for a hard spin. I tried some exhaust leak sealer but that didn't work either. Short of finding a new crossover not sure how to proceed

 

Without better picts everything said here is a guess however the crossover pipe could be bent wrong but it does not have to sit perfectly straight on the manifolds to seal. If this were my problem I would buy the repro left side manifold for dual exhaust and cap the crossover port on the right side and run true duals. Your engine will love it.

 

I've considered that as an option also. I have come across the manifold and cap on different sites but i've been on so many that i will have to research. I think e bay has the manifold.

 

...and to follow up, now that i'm looking for a repro left side manifold for dual i can't find one. Searched summit racing, partsgeek, amazon, ebay, walkers, dorman, and a few others, lost track.

 

Thornton Restorations is one, Parts Place maybe and Fusick, you may have difficulty finding the non 350 block off cap and may need to make one out of your old crossover pipe.

 

If a burnout is what started the exhaust leaking you may want to think about replacing the motor mounts too, if they are broken or worn the engine can shift stressing the exhaust.

 

Your right, i can't find a block of cap for a 425. I think I will start with the easiest solution first, a new crossover pipe. Although duals is an option i'm thinking that's more suitable for a 2 dr rather than a 4 dr sedan?? 'course that's not set in stone either...

 

duly noted and thanks.

 

You can always use a BB A body/442 manifold or 66-70 toronado manifold on the right side as they do not have the crossover port on them. Tucked under exhaust outlets like factory is no problem on a 4dr with duals. Makes a person think you have the police package on it! Resonators are needed to keep noise down though...