Had a big problem after the rebuild. The extra vacuum created by the port and polishing to the head, caused the steel air deflector under the second stage of the carby to break off.
The sheet metal component broke apart and was crunched by the pistons. Luckily for me, the metal is very soft and caused minimal damage. The deflector is there to help mix the exhaust gases fed in by the EGR valve, with the fuel air from the carby.

I have cut and filed of the remaining pieces of the deflector. I will have to obtain a deflector so I can maybe fabricate one with thicker steel, so that it will not fail again.