okay about the number4 piston and possible place for loosing coolaint

okay, well now, i havent check the plug above the pump, didnt realize there was one. anyhow, i drained off 2.5 oil pans, ya know the ones u use to change the oil with, ya that much fluid came out, first blackish then it was greenish brown, and thats when i dropped the oil pan and found the skirts to number4 piston and the oil ring, now i took off the intake manifold and there was rust around the ports, and after taking off the gasket underneath there was a ring of rust, now you said to drop the crank why?? and i dont need to remove the cradle, there's enough room, and by now i can get a cherry picker as i call it and bring out the engin in the front, everythigng in the front of the engine is disconnected, there is some scratchin on the lower cylinder wall, dont know what happened, perhaps pump failure. It was bored out to .040 before, i wonder if the one cylinder gets bored to .060 does all the rest have to be. sorta new at this, or perhaps i can get away with a bottle brush, I am about ready to stick a fork in this ole van, and grab a newer one. getting to the point of hey do i want to sink another grand into a rebuilt of course look at the prices of newer ones too.
and its really carboned up inside the valley and along the walls underneath the manifold intake.
When i cleaned the pushrods, there was some noticable scraping about an inch long thickness of my finger nail and the pivot balls ,all but two had these cuts into them sorta half moon cuts, but two cuts in each, rods were not bent but 4 of them were plugged, man how did all that dirt and grime get into the engine??, seem perhaps i have an ehausting issue too.
well thanks for the info before
paul.