I apologize for the lack of clarity.
Most of the time, in my experience, B18\B20VTEC threads go like this:
omgokSO, i ahv a spair b20 blok around and wanna maka b20VTAK! i alredy have a b16 bomber swap in my civic hatch, so i'm just gonna pull the bootom end owt and drop the b20 in, rite?? cuz like, i only have today and tomorrow off (btw it's 11pm) and my car musthasta RUN or i cant go to wrok! do u guys thynk i can make 400hp tomorow?
So as you can imagine, I get a bit... dry, with these threads. This is a subject of engine building, not a quick to-do under a shade tree.
A lot of considerations, a LOT, need to be made during engine design\part selection. For instance, everything on the belt side has to match the head (except timing belt, that can't be a B16 piece, even if your head is, hence, this is a consideration inside of a consideration). Likewise, the head gasket is another choice you can't just make, there are calculations that require the head gasket thickness as a variable, etc... Also, the matter of plumbing oil to the head is something you have to deal with, as is positive crankcase ventilation, fuel and oil demands, bottom end structure, mounts and linkage, this is simply not a motor you could put together as easily as others. You don't just go shopping for parts for one like you would at Kroger, it's about research, math and what you want to do with the engine when it's complete.
Once the engine is assembled, installation into a chassis, any necessary wiring work, addition of fluids and otherwise general buttoning up of a swap shouldn't take more than a section of a day. Like, an afternoon moving into evening, etc... Even in the machine shop, the work being done prior to assembly doesn't even take that long. But from the decision to do B20 (or LS) VTEC to having it running in your car, simply isn't a short affair, not if you want it to be RIGHT.
See what I mean?