CNC Mill Mark Removal in Intake Port

pittsburghracer said
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

And when you sink the valves, the valve stem ‘gets longer’, the valve spring is less compressed, the vacuum can suck the valve open a little bit and you can gain low lift flow. For a while it seems like you just hit the jackpot and found a bunch of flow - until you realize what really happened.