I`m considering buying a new dizzy this year, what I have now is a Mallory unilite non vacuum advance, thou its been good I really need a vacuum advance, besides its been in there for ten years, and I don`t want to get left out in the cold when the eye decides to quit, its original, I value your guys opinions, I think I can get an HEI in there but will need to check, would you just buy another unilite with vacuum and save the old eye as a backup, or just change out altogether...?