Take off all the sharp edges, also do that around the hole the injector sticks down, the sharp edges will become brittle under the heat.
What grit are you using? Make sure you don't polish the intakes or the fuel will not atomize and that will cause a lot of issues. I used 180 on the intake, and 180 and 360 on the exhaust, I also finished the exhaust up with a small flapper wheel which polished them to a mirror finish, you can do that to the chambers also. It's a lot of fun. I have over 40 hours in my alum heads, port matched to my lower, polished the exhaust and chambers cleaned up the intakes really didn't do a lot of porting, just evened everything out. Mine are going to TEA this winter.
Good Luck! Enjoy!
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