I do not think there was ever a factory update for the helix on the 07's. But I changed out the straight 44 to a 44-40 for cheap on my 151. I just put a post on here looking for a 44-40 and got a reply right aways as a lot of guys swapped out their 44-40 helix's on their 159's. I think I bought one for 50 bucks plus shipping. I think it helped out the clutching quite a bit on my sled.