KNOCKING NOISE?

I took my car to the track yesterday and ran the car bout three times. I was having problems launching the car all day. On the third run I missed second and kinda grinded it a little. After the run I noticed a knocking noise coming from what sounded like the cylinder head right above first piston closes to the distributor. When the car idles it does not make the noise. When I push the gas n a good amount while driving in a high gear it doesnt really make the the noise, but when I am maintaing a constant speed it makes the knocking. There are no leaks and never sound as if some blew car finished run fine. The head is stock b16 besides ctr cam shafts. The bottom end is built with eagle rods, je pistons 11:1 copression, and a eagle block guard. With like a ls girdle or something for protection on high reving. The motor has about 35,000 miles. What seems to be the problem?