What blocks do I have

Got it! Sorry for the confusion. Got a snap gauge which is easier than an inside mic and everything is "good in WHO land".
Block reads .020 - .027 oversize with .005-.007 taper. I'll shoot for .040 oversize which should allow enough meat for a clean cut. I like the idea of a 500ci kit but will stick with the 451ci.
Thanks for the comments which allowed me to get my head straight.