I recently took a risk and traded a $300 trash pump for 2 hydrotek hot boxes and a 525 gal water tank. I was told the burners didn't work but maybe I could use one for parts and get a working one out of the 2. So I cleaned the coils and burners inside and out and rewired them. Now they bolthe are working. The only problem is they are the 14" models so they can't keep up with a high gpm machine. So I am wanting to "hot rod" them. What's the max burner nozzle size that will work?