leak down

so about a month ago I scorched the head and blew out the head gasket. I had the head welded and machined with 2 new valves in the number 2 hole. went out last weekend. after warming it up on Saturday I did a leak down. number 2, the hole that was hurt leaked down at 45. 4 6 and 8 were all still pretty high 25-30 percent. 1 3 5 7 were all low between 10-18 percent I believe. we ran it on Sunday. kept a fat tuneup in it as I am a top sportsman racer and not worried about qualifying to speed for that matter. went 7.05 7.05 and 7.19. which usually its down mid 6.80/90s in that kind of weather with the same tuneup. I have one last big race oct 2nd and 3rd where we qualify 2 rounds on Saturday and run into eliminations on sunday. my engine builder says leave it and we will pull it apart after that weekend that we wont hurt it anymore running it 2 more days. I have had other recommendations to pull that piston, put in a spare piston with new rings. or pull that piston and re use it if it looks good with new rings? any thoughts or recommendations?

 

The important question is where are the leaks? Rings, valves, head gasket? Ring leaks are usually the least serious.

 

Thank you guys. we had the head welded and machined. did a full valve job with new valves on that hole. new head gasket. so im assuming it is the rings. I am going to pull that piston change the rings and check the bearings.