No real secrets in a solid build, top engine builders will measure and document every measurement and have their personal settings for a lot of clearances
For a straight forward Block/piston/cam swap Hardest part is degreeing the cams
go on youtube and watch a SHEIT load of videos on how to do it. If you seem comfortable with it.
FOLLOW THE MANUAL STEP BY STEP for motor removal and disassembly to the cyl removal, reassemble with the new parts after gapping the rings, MAKE SURE YOU ARE CAREFUL sliding the jug down
84mm is a little harder than stock bore because there is less chamfer on the bottom of the jug to help compress the rings