Newbie help...

Be sure to watch the temps running that 7L in a truck. I have an 8L in my buggy when I first converted it and destroyed two or three 3S2P 6Ah packs. That setup will draw some current when you run it hard. Just my experience, you may have better luck. I'd try to make the move to 4S as soon as I could and get an XL can motor. I think that a 7 or 8XL will do nicely on 4S, depending on how fast you want to go.