I’m wondering if anyone has a clue as to why I have little pits in the piston and cylinder head.

Boosted sleeved b18b 84.5mm bore with b18c1 vtec head, only had 2500miles ish when it blew

I spun the cylinder 1 rod bearing on the track and I’m rebuilding the engine with a new rod and crankshaft, but these pictures are from cylinder 4 and only has the pitting on cylinder 4 which had good compression and the valves hold fuel. Any ideas?

 

The only thing I know to cause that is detonation. Either an ignition issue or running lean.

As to why it's only on cylinder 4, I can't tell you.