I too have been accumulating knowledge and parts to build a modified engine, a 230 in my case. I've heard some pretty radical numbers about how much can be shaved from the block and head. But I'll probably bite the bullet when the time comes and spring for the Edgy head so I'll take measurements at that time and go from there, whatever's necessary to achieve good quench within safe clearance limits. Don't relieve the block on these.
Some folks say to cross drill the cranks and some say no, it weakens them. They say instead to cut grooves in the upper bearing halves, so I don't know. The jury's still out on that for me. There are some very knowledgable folks here on modifying these engines. So be patient and I'm sure you'll hear from them.
Likely you already know that there are aftermarket intakes, split manifolds, headers, etc. available too. I'm building my own headers because I want longer primaries than what's available new and because it'll be in a fenderless hot rod, so they need to look "cool" too. I also found a sweet set of new finned aluminum side covers for $50 on fleabay, likely the same ones that Stovebolt sells for $90. Thanks to a member here, I also bought a nice vintage Tattersfield intake which is just too cool. The goodies are out there, just look around.
If you're able to go back standard, I've got a NOS set of Nyler replacement pistons for 218-230. I'll need to overbore some so they're not an option for me. (Looking for some +.060, anybody?)
Vintage Power Wagons has just about anything you could need for these engines as far as replacement parts go. And they're pretty reasonable on most of it too.