need more power

pulley swap F2 to FE is a BAAAAAAAD idea. Crank pulley is the harmonic ballancer as well for these engines, and it is CRITICAL that the one that came with the engine be the one that is used. Although they would bolt on, one can only safely use a pulley that was ballanced for the correct crank. IE, one from a 2.0 should only use a 2.0 crank pulley, and one from a 2.2 should only use the 2.2 crank pulley.

Power gains on these small engines is limited to a cam/carb/exhaust upgrade. Pacesetter would work well but to gain full benefits one needs to get the cam and the correct carb as well. The 38/38 is overkill for the small engines, but I have seen it done with the right cam and exhaust setup that made it a lot faster. With that setup you could keep up with traffic and pass at 80mph a lot easier, but that's it.

Yes I have to agree with Charlie, a slug is a slug.
It can be a shiny chrome slug or even an expensive turbo'd not-so-slug-ish, but this motor was never designed to make H.P.
Pass the smog requirements and make torque enough to pull around a fairly heavy body and its load. And get good MPG. It's a tractor. Technology is king and even in the day that Mazda built these B's there were some nice motors out there, B16 vtec ,165hp, KA24DE 2.4 makes 165hp or even the single cam KA24E 135hp. Toyota made a sweet big 4 banger, smoother, quieter, torquier. And of course the SR20DET or the Prelude 2.2 vtec, 200hp.
The mazdas just start out way down the ladder with a 2.2 making 86hp. 12 valve head swaps, fuel injection, turbos. It's a lot of fun doing this, what mazda should have done, but you spend lots of $ and then your even with these other guys.
Owned my B for years, I except her for what she is.
I have made her a little better, a little more dependable, a little faster. But if want to chirp the tires, I would think engine swap.
This is not to belittle all the work you have done, I'm sure any of us who drive stockers would be impressed driving your B. Probably say wow, whats wrong with this?