No, there's nothing wrong with giving the size in cubic inches. But that's kinda obsolete; even the American car makers don't do that anymore.
But we're pretty tolerant around here.
And it does lend perspective, now that I think about it. I remember an old LTD of mine that had an engine equal to 100 66cc china girls. It really is pretty impressive that an engine even smaller, in my case (3 CI), can haul me plus a bit of a load all over town.