Bought a new dryer and of course it has a 4 wire pigtail. Is it necessary to change the old 3 wire rec in my house, or can I just change the 4 wire oigtail to a 3 wire off the old dryer. Now if this was the opposite situation, I would have no problem. Bend the ground strap back, neutrtal to the middle, ground to the cab , good to go. Where I am a little bumfuzzled is do I put the green ground on with the white neutral at the power block?