This past weekend of racing I had a problem with my car. First pass it ran 11.16 @ 119mph which is about normal for 4500 DA. Second pass the car slowed and really labored down the track to 11.57 @ around 115 mph. On the second pass it also kicked the breather out of the valve cover and oiled the under side of the hood. I put back in the
breather and limped back to the pits and loaded up on the trailer.

I tore the car apart tonight and at first only noticed the head gasket burned between #4 and 6 cylinder. After I turned the motor over to check the pistons I noticed # 6 was burned on the edge. I am assuming the piston burned up first then the head gasket. What do you think?

I had ran the car with nitrous earlier in the year around May. I thought I was conservative on the tune up every time. For a 100 shot I dropped the timing from 32 to 26 degrees and jetted 53N 47F with 5 1/2 psi fuel pressure. The plugs looked good. They were light and the timing mark was about an 1/8" from the tip. With this tune up the car went from 11.05@ 120 to 10.44 @ 127. I also tried a 150 shot once. I pulled another 2 degrees(24 degrees total) and rejetted for 65N 59F. The car only picked up a tenth and no mph. I thought this was do to the converter being too loose. The shift light stayed on from when I shifted to second and stayed on the rest of the pass. I only made the one pass, since it was no real improvement and have not sprayed the car since.

What gets me is I have made at least 50 passes since then and the car ran has ran normally. Is it possible the piston has been melted this entire time?