Bummed Out ! I SCREWED UP !

This is only my 2nd Big Block and bottom line is I screwed up. I intended and should of checked this clearance early on in the build. I took it for granted this combination of parts, being somewhat conservitive, would not have any clearance issues. I did however install light check springs on my No. 1 chamber intending to double check clearance before I installed the gasket and torqued the head. I was checking pushrod lengths and valvetrain geometry when I discovered the problem. I pulled down on the rocker tip with piston aprox. 10 degrees before TDC, TDC and 10 degrees after TDC, noticing a minimum clearance. I set up a dial indicator on the top of the rocker roller and what I discovered is .015 to .020 clearance. I know sinking the valves hurts performance and I guess that would be the wrong way to go. I do like the cutter ideas (Thanks for the sugestion). I will need to pull the heads and take a closer look. Hopefully the amount of material removed wont amount to much, as I did have the rotating assembly balanced. I wont forget this lesson anytime soon. Thanks for the input and suggestions I appreciate the help.