383 water pump help

[70 RAG TOP]

 I have  11/69 dated 383 with a waterpump casting # of 2780987 and an impeller w/ #3671083.

My challenger shop manual states that a 383 4bbl should have an impeller w/ a diam of 4-3/8" and 8 blades.  The one I have (#3671083) only has diam of 3-1/2" and only 6 blades.  I have had problems with overheating. 
Question:  Would  changing to a larger impeller(4-3/8 w/ 8 blades)  make a noticable increase in cooling ability?

Thanks in advance

mike

[Chryco Psycho]

it definatly can make a difference , if the impellor is too small it can bypas in the pump as well