I have the predator 420cc which is supposedly rated around 13 HP, but varies since they all use the same displacement and different compression ratios and what not. I don't ride my kart much since it needs some upgrades because this engine has too much HP for a dead axle.
Anyway, I look at this engine like something that was designed to put out large amounts of torque w/o revving higher than it was intended to. (If I wanted something that revs fast and loud, I would've found some kind of 2 stroke). I kept the governor in tact and 38 mph with a 6:1 ratio is pretty good to me.
I highly recommend it. The only thing you'll notice is that this thing burns probably twice the fuel since its more than twice the displacement than a 6.5 Honda. Other than that, the electric start box is really cool. Especially when you lengthen the wires and connect it right under the driver's seat. Never again (as long as your battery is charged!) Will you have to get out and pull that rope to start your cart. Good luck on your purchase.
Edit: something that id like to add s that these engines are cheap for a reason. I haven't used a duromax engine, but for $229 or w/e it was, sounds sketchy. These are chinese-made and I can only imagine the quality of the parts is low. I would certainly go with the predator 420. 1. Who doesn't want their engine to say "420"? XD 2. This is a more popular brand since it's HF's. 3. I was shocked how much torque it gave me.
