depends on which dewalt motor you go for, they're 820 size. the 700's are smaller. I run a single which seems ok.
Many video's on you tube. Want speed use the 12V, want torque go with 14.4V. both on 4s.
You may need a motor mount. The brushes wear down quicker the more volts going through it, but at about $5 a set it's still decent.
Overall there's maybe 15 dewalt motors that work.
I run a single, and currently working on the twin dewalt project.