help with radiator replacement

I have a 1976 Dart Sport with a 225 /6 in it. Don't know too much about this car as I bought it last year and haven't drove it much but it has run fairly well but now that the temp is getting warmer outside the car runs a little warmer than it did. The car has not been serviced as well as I would have kept it. I believe the previous owner has had it parked at times for awhile but, it has the original radiator in it. part # on it is 3869906. It has the original radiator hoses on it and I would guess it has the original thermostat in it. I am going to replace both hoses, thermostat and the radiator in it. I believe it needs to be flushed. I am going to do all of this but in buying a new radiator I am guessing will have to go with a 22" now. The one in it measures about 19" wide so is that the new replacement size I need to look for. I was thinking about an aluminum one for it. any suggestions. Maybe a Champion. I believe this is a 2 row. any help would be appreciated. This car will be a daily driver of about 65 miles a day on the interstate so it has to be right. thanks