I've run a single dewalt 820 in my truck. On 14cells its a touch quicker than dual titans and a lot more torquey. Have a look at
www.kershawdesigns.com , the guy that runs it (Dan) has lots of big brushed motor conversion for the maxx/savage.
But I speak from experience when I say there is NO comparing brushed to brushless. Once you go brushless, you will NEVER go back - it really is worth the extra money.