fuel pump...old or new style

[hdrider]

in reference to my last post i did some digging & found that the fule pump that came off my 1982 GMC came off a whole list of 1976 & earlier GMC vehicals...can anyone tell me if this older style is, or is not better than the newer style...being that the only difference i can see is that the cannister on the older style is over twice as long as the new style...is there a difference in the rate of flow ???...........thanks