Ang alam ko medyo mahirap ang spare parts for the Mazda. We have a Mazda B2500 which cracked a cylinder head and we had a real hard time looking for a replacement. Wala sa Davao, Cebu or even sa Banawe. We had to buy an original head from the factory for P51,000 and had to wait days till the part arrived from Japan. This vehicle is a pain in the ass because mahirap maghanap ng even the common parts. But who knows, it may be a different story for your B2200.
Perhaps you can canvass the availability and price of the spare parts that you will likely need before you dismantle your engine. That way you can be sure of its availability and the money you have to spend.
I also read in a forum somewhere that surplus B2200 engines go for only P18T somewhere in Pampanga.