blown head gasket

[Mike-]

which bit are you looking at on the first pic?

[Alex B]

Has that rocker cover look about it to me.

[Dell'Orto]

Dont worry about it, just get the next oversize piston set, get it bored to suit and slap it back together.

[fangsport]

guys, it's a 4K. unless it's had plenty of other work done to it either buy another motor or hone and re-ring it. by the time you rebore and get pistons you my as well get bearings etc , which will all add up. chances are you might get away with just a head gasket, but it will more than likely be smokey.
where abouts are you Mike? have a few short blocks here if you wanted to swap the bottom end.

[Mike-]

to clean out the cooling system, can i just squirt a hose down the holes on the right side of the block, ill cover up all the others holes and cylinders first.