bench your head and ill bench mine. we can compare.

 

Just look at some AFR, Trick Flow, or L92 heads, most have a somewhat D shaped exhaust port. When you drop the floor of the port you lose velocity.

 

So easy a caveman can do it!

 

You could have that welded. If you decide to take it to a shop, ask someone what they would use to weld it. If they say to use 4043, I would suggest to not let them weld it. 4043 is the most common filler rod, and is not suggested to be used on heads. If someone suggests to use something like 4047, that is the person to weld it. They know the difference, and will know if they can tackle a job like that properly. I would not be worried at all to use that head after it was welded. Even if you decide to not use it, it will be a fun piece to practice porting. Good luck with it.

 

If only it were on the intake side...would make a badass carburetor with the right squirrel operating the hole.
To the OP...nothing ventured, nothing gained. I think its kick-*** for you to have tried porting your own head.
edit: Would this be considered "hitting water"?