Hobby star makes a 4274 1500kv motor that can run 8s, I just got a used machete 4s, and that's what I plan on doing. You will also need a long shank pinion to run a different motor.
Just got the 4s version in the mail, new 4s lipo batteries arriving tomorrow can't wait to rip this big boy .... Also with 8s , I'm already planning on flipping the motor module around drilling new holes and mounting it then you would be able to run any length can you want