the one I have is came with a 6'' shaft auger shaft and cut . wondering if I can move up to a 7'' shaft and auger without overpowering the motor . also the 7'' auger I am looking at is a strikemaster but the blade is not the same as what I have now . my 6'' has a point and 2 cutting blades while the 7'' has a point and only one cutting blade . is there a difference between gas bottom ends and electric .