I ran mine 60 over for 6 years in my race only Dart. Never had a problem until it blew up. For 2 years, I had some used super stock pistons with the domes milled off. Then I bought some new TRW 13:1 slugs. It finally broke a rod near the small end. It quit right at the finish line. Externally, it didn't look like anything was wrong. When I got it on the stand and rolled it over, it sounded like it was full of gravel.I had to pry the pan off of it. There was nothing left inside. I was able to reuse the valve covers and intake.