RE: K&B .40 DELTA
OK, now that I had a chance to make you sweat about the rod mod, I'll tell you what really happen. These engines have a nice shiny band around the bottom of the crank to "stuff" the crankcase. Underneath the band is the cutouts on the crank disk to provide the counterbalance. What I think happen is the band broke (seemed to be a problem with the engine when prop'ed above 21,000 on the ground according to others at the time. With unload, they would be about 26,000 in the air. Anyway, that one was prop'ed to run slightly above 22,000.
Your mileage may vary. Of 10 K&B racing engines I had, this was the only one that split and spit it's guts out.