tgilligan

I have noticed some exhaust leaks at the flanges between the cast iron manifold and the downpipes. I converted my single to dual exhaust and looks like both flanges have small leaks. Are there gaskets in these sections or are the flanges supposed to seal it? The exhaust was installed by a shop so I wasn’t there to see what was there originally.

olds 307 and 403

Later 3 bolt flange do have a gasket, early
2 bolt flange and cross over pipes don't

joe_padavano

A-body manifolds are metal-to-metal. Some manifolds for full size cars do use donuts. Trust me, if the donut was missing, you wouldn't be able to tighten the bolts on the flange.

tgilligan

Thanks guys. What is a good method of sealing up a leak at the flange on the 2 bolt flange?

joe_padavano

Walker Acosti/Seal

tgilligan

Thanks Joe

Sugar Bear

X2 on Walker Acousti Seal. It is THE go to.