Gary,
Welcome to the board. You will need to rebuild sooner than latter. Did mine at 84,000 due to 2 broken head studs. The valve guides were shot and I was using a quart every 600 miles. 500 miles will probably not hurt the engine. The possibility of damaging the valves or seats is the only thing I can see happening. The guides let the valves move too much. Get Wayne's engine rebuild book as there is so much valuable information even if you don't do the rebuild yourself. Also plan on replacing the lower 12 head studs with steel studs as the dilavar exhaust studs are going to fail. Do use the search button to find hours of reading on rebuild questions.
Also we need to see pictures of your car before we can answer more questions
