You have a two inch pulley on the back and want to do burn outs.
You have gone too small on the rearend.
If you want good speed and low end power to do burn outs or carry the front wheels 20 feet you need to go with a 3 inch in the back and a 4 inch on the engine.
Craftsman is not a good choice for doing this. The front end of the frame is going to crack and the axle will twist.
I have built many mud mowers and have to tell you this is not safe your going to get hurt.
There are many mods you need to do before you make it go fast.