if you put a pal rom on an american board, will this work in american systems? i have already done this, but my nes has the lockout chip cut, so i dont know if it works with unmodified systems.
Some games will work. Games that weren't also released in Japan or North America might fail because they do too much in the vertical blanking period. The game will run 20 percent faster. Complex raster effects based on CPU timing might fail.
I did this with a version of The Smurfs and it runs faster.
Using an american board with an american system will just avoid lockout cuip issues. Whether the game will run or not depends on how it was programmed.
Probably very few games adjusted themselves automatically for PAL or NTSC systems, which means that most games will indeed run faster. The ones that rely on lots of Vblank time will probably have very corruped video. And the ones that rely on timed loops will probably have some visual glitches.