How do I run the LEGO Technic V6 engine using a Lego electric motor?
Assuming that your motor already has a Technic axle available, you'll need:


Any Technic motor. You probably want an M motor (8883).
An appropriate battery box or other power source. If you selected the above motor, you probably want the PF battery box that uses AA batteries (8881).
Any Technic elements that you want to actually mount the motor onto the V6. In the case of the above, you could get away with a shorter axle and a few Technic pins. If I were you, I'd either purchase a small Technic set (e.g. https://brickset.com/sets/42088-1/Cherry-Picker), or an assortment of Technic elements on Bricklink.


Most Technic motors aren't especially fast (~400 RPM). If you want an RPM up in the thousands, you'll need at least a couple of gears as well.