The Blocky 2 comes with the same bore size as the Blocky 1.....which is the same bore size as the Raptor.
The Blocky 2 has an improved bolt pattern......and that pattern can be rather easily used on the Blocky 1, and head.
The 3, is the 3" bore, and is the bore half of the infamous Blocky 3X3 engines.
You can obviously get a superior 14.5 engine from the 1 and the 2. To get the big bore 3 down to 14.5 you'd need to run a destroked crank. I expect that an Intek/Animal/WF 206 crank would get you there.