Fan spacer size?

A little tip, The further back the fan is from the radiator the more air flow you will get over more of the radiator and I know this because of previous heating issues in which this did the job with no further heating issues. ex: if you have a 26" rad with a 16" fan your air flow coming thru is pretty much contained in that small area leaving an overall of 10" (5" per side) of your rad without much flow where moving your fan further back will increase the air flow over more of the rad.. That is MO..