Head gasket replacement

[genegr]

I have a 85 740 GLE that runs great but looks like a little leakage coming from the head right below number 2 glow plug. 168K miles and looks like the original head gasket (two little notches). From my reading on here I gather I won't be able to order one until I find out the piston height? Is there a gasket set available for the entire project? If I get the flywheel set on the mark and number one at top dead center, mark the belts and pulleys will I be able to unbolt/bolt everything(fuel pump) back on and get it to run? I have not been able to find anyone that will work on this beast and I don't want it dead in the garage for a long period of time. Thanks for your advise.