No matter if you buy a 100 or $2000 distributor if the curve is not right for your engine it will never run optimal. Like matt Graphed the MP or Mr. G springs are seriously light and advances all in fast. There are dozens of different springs that mopar made. All sorts of combinations but you also have to know what your advance plate is. Say it is 11, and you need 15 dist degrees, you either have to change it or get the slot milled longer. There were a good set of springs I found a yeear or so ago they were Blue Dot. Pretty much a decent curve in most not to light and not to heavy. As of different weights no selection I know of out there they are all 69G.
