This thread turned into being a better thread than I thought it would be lol, good info on here.

Internally, are the newer (no oem breather tank) blocks identical to the older (with oem breather tank) blocks? Like all the oil passages and such. I am guessing they are and that honda just simply put a freeze plug where the breather was to cut costs. I have only worked on the older blocks with the breathers on them.