Would a 3mm overbore help with the head work?..

ie -its more room for bigger valves without notching the block-

and more room for chamber reshaping, valve deshrouding etc

plus the bigger overbore will increase the C.R. (with the bigger displacement) with flattops anyway

All that should be able to be done on an L28 block with out the over bore.

Yes! The crank scraper is only held on by the main bolts. I ordered this scraper for the LD28 crank but it had to be fitted to the "throws". I also use the aluminum pan with a nice set of oil gates.