got my mach back from horizon finaly and ive got about five tanks through it and im starting to tune it. it runs great plenty of power but the problem is i cant get the temps below 270. ive richend the hsn and nothing changes truck runs like crap but temps stay high. can any one help

You have an air leak somewhere. Try this..Take the pressure line from the exhaust, plug the throat of the carb with your finger,and blow into the pressure line, chances are youll find your leak. You could also, if you cant find it like that, get a spray bottle with water and a little dish soap in, spray common areas known for leaks (back plate, carb, where it mates to the block, the primer on the tank ect.) Do that without fuel in the tank of course

After checking for air leaks, cut a vent hole in your windscreen.

You may also want to check your LSN to make sure it isn't too lean. The face of the screw should set flush with the carb body.