
You can see where the valve was hitting the piston on all cylinders. No 2 valve head failed and fell off, bounced around a few times and ceased the motor (it was only idling when it broke). The timing was out by a tooth which happened during installation after timing had been done. There was no noise at idle, only on the track at revs.
The valve and piston were hitting above 4000 rpm but it reved to 7500 before some power loss was felt, which would have been a bent / jammed valve.
The head has been welded up, remachined, new valve seats, new exhaust valves with one intake. New pistons and bearings in the block. I'd expect to see a similar effect on your pistons, as no 1 in this photo... maybe not quite as bad as this as it was pushing some high revs.
NA8: N/A 200whp | Haltech | Skunk2 Intake | S90 TB | RCP | 5 speed c/r dogbox | 4.78 diff | AST Shocks
Barbs L: 64.12 | S: 58.62 | Collie: 49.72