Oil leak between head and exhaust manifold
 

Hi guys, hope you’re doing well.
This one is a new one for me. I can’t figure where an oil leak would occur where the exhaust manifold meets the head. It’s definitely not the rocker cover. I put a new gasket on it and have monitored for any potential leak at that point. It seems like it’s bubbling out at both ends of the manifold. Any suggestions?

Sorry, forgot to mention it’s a 400.

And you have no oil smoke out the exh pipes?

Since 1964 or 65 there has been no pressurized oil passages in pontiac heads for such a thing as you report to happen.
Did you just put the heads and exh manifolds on this motor?

Did you lube up the exh manifold bolt holes in the head with oil?

If so once the oil gets up to near exh temperature it will boil and force its way .
Does this sound like what you have going on?

If you have access to a smoke machine, this would be an ideal task for it. Smoke the engine and the leak source will show itself.

What heads are you running ?

Are they 1972 7K3 heads that have had each exh flange end pad drilled and tapped for a bolt holes?

The smoke machine is a great suggestion, but where the hell would you start?

Sure it's not condensation boiling out on startup, turned dark by carbon? Other than valve seals bad enough to allow enough oil to fill the combustion chamber, that's all I can think of.

Them valve covers can drip... around turns too.

Yet I figure ya could be running rich for soot generation that manifests at the EXH gasket leaks.