motor for x pro

[mikerobinson83]

i have a converted 4wd nitro i run in the winter as our track is outdoors,
using an ezrun 5.5t but this is going to be far too hot for the x pro i intend to use for next summers racing

so what turn motor will be best for 2wd?

i was thinking 8.5 as our track is neither open or tight or would a 7.5 be better?

thanks mike