That sucks, i'm kind of thinking your engine is slightly too hairy for hypers... 6200 RPM with a 4" stroke is pushing it for piston speed, throw a little detonation in there and POP!
I broke a 360 with KB hypers as well, had too much compression for the small cam and pinged it to death; ran for 25k miles though. It finally broke a ring land, seized the wrist pin and cracked a cylinder which flooded the pan with coolant, but it still ran! Kind of even still had some balls to it too, ignoring the awful racket it made.
