Never ending story

[Belgium Cuda]

After rebuilding the 340 some months ago I never got the right side headers to not leak towards the head. Cheap ****headers but I tried everything
including coppargaskets and even double standard ones. I mounted the original exhaustmanifolds and I got the exact same leak 
The reason for rebuilding the engine was that one head was "bended" due to overheating so I bought a pair of Indy rebuilded 318 heads, complete
with bigger valves. Now I start to think that my leakproblem sits in the head and not on the manifold as I first thought. Any thought about this? 

[matt63]

I would check to make sure the headers are not hitting something that would stop them from pulling tight against the head (like a scattershield).  Other than that, if the heads are reasonably flat and the header flange is not warped it should seal.

[Belgium Cuda]

Thats why I mounted the original exhaust manifolds, they are flat with a big sealing surface but still I have a major leak. I start to think
it's a crack in the head? 

[matt63]

What are the symptoms of this leak?

[Belgium Cuda]

It's like you didn't tighten the bolts at cylinder eights exhaustport, you hear it and feel it if you put your hand between firewall and exhaust
manifold.

[Moparal]

What year heads do you have? some had small holes under the ports for emissions and need to be plugged as i recall

[Belgium Cuda]

If I look in the book they should equal heads for a 72-73 318. My engineshop didn't tell me about plugging anything and the other side is OK looking the same.

[Moparal]

See those little holes under the exhaust ports? Are they holes or where the manifold holes were covering. But those little spots are where exhaust emmision holes are . See if yours are solid or if you have an actual hole there leaking.

[Belgium Cuda]

Thanks, will check this out and come back.