Engines out........
Remove the sump 20min
Remove the pump 5min
undo one big end cap ......pop the piston out 10min......there done.
Check the big end bearings on condition and crank as the others come out.
If bearings are good,you can re-use or slip new ones in.
Do not disturb bearings and remove from rod or cap if you re-use.
Re hone pots and slip new rings on.(check your piston size)to get correct rings.
Don't forget ring gap is ok.
You can do this with leaving front pully on and flywheel.
I think a little rock is fine unless its a race engine.
If i lived nearby,i would do it for you in afew hours,but you have to scrap
the gaskets
If you do this,you could fit a little washer under releaf valve
spring on pump for that little better pressure(suggest you give to someone that
knows,if you don't).Will not hurt.
Not a full re-build,but a wise thing maybe while out.
Good luck.