Piston pin bad ?

I don't think the failure was the original builders fault , but rather a random comedy of errors.

I do however think that the engine might have been a dog and possibly lived a short life due to poor workmanship....

Who knows where that piece came from...i was very carefull and even taped up ports once heads were on!

Yep,, chit happens,, you'll likely never know,, but check those butterfly screws.. lol .. hang in there..