My Mopar Performance electronic ignition came with heavy springs. Didn't get all of the advance in until about 4,000. A trip to O'Reilly Auto Parts and $6.00 got me 2 light springs from Mr. Gasket. I just used 1 from Mr. Gasket and the lighter one that was already in the distributor. Now all advance is in by around 2,500.
If it has a gold plate inside with 2 hex screws & slotted channels, then its the HP MP dizzy, i ended up getting one when i purchased the MP dist. kit awhile back, i think they were made by mallory, it had the lighter springs/weights, you could also lock it out, it was really nice the way it was set up, total timing was all in about 22-2300.