If you get a 4s capable motor, maybe. But you would need to upgrade transmission parts like asap. Most like to do a 272R swap. But for 4s most are 42xx diameter motors and would need to mod the motor mount inorder to fit, unless if its a 36xx diameter itll fit fine. Ie Max10 G2 140A with a 3665 2400kv. Also 4s on a 2wd slash? Yea its gonna spin like crazy and you need quite the experience to handle it. And it will be super rear end heavy due to the large motor. Would also need a bigger battery strap/tie down, ect.
imho, 4s is way too much for a 2wd 1/10. 2s is plenty, especially if you have a high kv motor. 3s is insane too lol.
I run 2s with a HW 3652 4000kv. Pretty conservative gearing (20/86) plenty fast, speedy and stays cool for days.