Alas, the NTSC version doesn't actually work on NTSC consoles. The NMI timings have been changed to work with some (but not all) emulators in NTSC mode, but it isn't a full NTSC conversion, it's an NTSC emulation (at least, that's what the authors call it in that version's scroll text).

There's a full list of differences between the PAL and NTSC versions here:

https://github.com/markmoxon/nes-elite-beebasm/tree/main#dif...