Looking for information on blocking the center exhaust ports on C heads.

 

We blocked the intake center ports with sheet metal, but there are many different ways to do it. Some gasket set can be had already blocked off, sure some with more knowledge will chime in, could also use search feature.

 

Do you mean filling in the center divider...or filling the heat risors? Two different things and two different operations. Regardless, the final machining should be done afterwords.

Filling the divider is usually done by brazing or welding to build up the surface and some finish grinding to size.



Filling the risors is pouring molten aluminum or some other alloy in the head and then finishing it.



These picture were taken from this post. Its a good read.
https://classicoldsmobile.com/forums...hniques-3.html