71 Dart 410 stroker ..

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....