How do I lap a modified head?

[blaster003]

got my motor back together and noticed I had a small leak coming from the head gasket but my question is how do I lap my KOR modified head? I also used a oem gasket head clearance is right and all bolts were torqued in correct sequence after each heat cycle I got about 5 hours on this rebuild

 

[best]

got my motor back together and noticed I had a small leak coming from the head gasket but my question is how do I lap my KOR modified head? I also used a oem gasket head clearance is right and all bolts were torqued in correct sequence after each heat cycle I got about 5 hours on this rebuild

It should not need a lap after 5 hrs, but here is how you do it.
IF the head sealing surface is not machined below the fin area:

• Lay a sheet of 240 (or higher number) grit abrasive paper out on a sheet of glass (flat surface)
• tape the abrasive paper down and move the head around on the paper in a figure 8 pattern