I need help on this one. My shop is puzzled. Old receipts show a good, professional head job, new valves, including Stellite exhaust valves, new pushrods and the supposedly uprated lifters and new springs. The pistons don't look like they got hit. But 6 valves are bent, including all four exhaust valves. What happened?
My cam was "probably" a performance cam, but I can't find that receipt. The car overheated badly twice, but I just can't imagine that was the problem. I shut down quickly both times.
I've had pre-ignition in the past (not in the last year or so), but I always use the clutch to shut down and only rarely did a have "run-on" for more than two seconds at most.
Ideas?