I'm in the process of porting a 1980 p/u cylinder head. I was wondering what to do with the small emissions breather holes in each exhaust bowl.
Is there an epoxy that will withstand the temp. or is this mod unecessary?
For port matching how far into the ports should I blend it.
Thanks in advance for any help.

t110@pennswoods.net

You can just grind down the tops of the air injection ports and then plug the main feed hole at the rear of the head. (tap it for a pipe plug or use the air tube flange and flatten / weld the tube closed)

As for the actual porting, use the intake / exhaust manifolds as your guide and grind away any sharp edge / mis-match where the manifolds meet the head ports. (use a gasket as your guide)

Most all of your porting efforts should be focused on the area *directly under the valve seat* where the machining meets the raw casted port. Grind away that sharp edge that narrows the port as it come into the seat.
DD

Thank you Doc. I am fairly new to this forum and really appreciate the expert advice that is shared. Should it blended around guide just enough to remove sharp edges? As always, thanks in advance.

t110@pennswoods.net