CNC Mill Mark Removal in Intake Port

I agree on the 2-3 mostly on account of in my case the valve opener. You have to use a strong enough spring to keep the valves closed and then it’s a feel, visual thing setting your valve opener to zero. I use cut lexan 1/2 entry plates with a little bit of Duct Seal so my plates are pretty consistent. My head adaptors use 4 head studs so they center everything up nicely