If the heads are off, would it be best to put the weld on the inside of the head, which would decrease the air volume slightly? Or might the heat soften the infused hardening of the head (e.g. w/ a ...302 head)?
The heads were on, and my thought was that the remainder of the hole would just fill up with carbon as time went on.
And yes, I ground the surface and filed it flush with the port...