71 Dart 410 stroker ..

70aarcuda said

Well..I am not sure if the valve dropped...the valve stem was there with the retainer and keeper in place...It looks like the head of the valve came apart....but I dont what cause it all...
I thought it had broken a rod...and the rod hit the head....cause at the track the spark plug looked like it had been hit by the piston....but the rod is fine...so if the exhaust valve head came apart....i guess it would wedge between the piston and head and beating up the spark plug....the cracked cylinder wall dont know if it was the cause or results of all the other crap happening...

so I am not sure if I want to sleeve this block....

Click to expand...

Tony do you see any signs of the valves hitting the Pistons lightly in any of the other 7 cylinders.
I did not see a valve to piston check in your build.
I had a friend with a big block chev had a failure just like that.
We found out the machinist had taken a light cut on the heads during a freshen up which decreased the clearance. It was not checked and we figure the piston hit the valve and bent it just enough for it to hang open on the next cycle and then kaboom it was all over.
We could see very light indentations on the other cylinders. This was the telling sign. Just a thought. Sorry about your luck.
Hopefully it can be fixed though.