Sure sounds like what happened to the 440 in my '70 Bee a few months ago on the way to a car cruise. I knew I was in trouble when I pulled the #7 spark plug and found the tip smashed. To say I'm NOT happy with 440 Source heads would be the understatement of the century... Small hydraulic cam and under 6k RPM. In my case, the #7 intake locks pulled right through the retainer. The head is now a paper weight. The #7 piston (SRP forged) has the valve embedded in it. Twisted the "6 pack" rod slightly and the bore is cracked.