What kind of blow torch to use for a stuck bolt
First. I would ensure that you are using a 4-way Tire Iron. It makes you apply equal pressure to the bolt and you will be amazed at the different. In fact, if you have not tried this. Then i would not worry about the heat source for now. 



In terms of the blow torch. you need anything that can throw enough heat to make the bolt almost red hot (note I say almost) 

A butane torch will be totally fine. Just watch out, the hot nut will be a little easier to snap when hot.