ramrodDon't expect much improvement over standard level unless you're ready to spend huge cash.
The limit of the above unless spending lots is about 160hp and that will mostly be at the upper end of the powerband.
That's where most people stop when building NA redblocks
If you get bored of that, you're going to have to get into the headwork which when paying a professional will add up to four figure sums pretty quick, I would use the B230 block as well due to having bigger bores than what you currently have. For more low end
Regarding shaving the head for higher compression, I've shaved off 30 thou myself, but I have seen people take off 60 thou and even beyond that. When taking off that much, the cam belt tension becomes too loose and there is a shorter cam belt you can use to compensate.
Keep in mind the camshaft you select will alter the dynamic compression ratio.
If I were you I would rebuild the B230 block then get it going for a baseline, taking it to get dyno tuned would help to have a starting point for future mods
Just for reference if anyone is playing along at home the shorter square tooth belt is a ford cortina belt gates part number T013 readily available in aus it's 1 tooth shorter then a standard b230 belt