Keep this in mind. If you buy aluminum heads you still have to have them checked out!!! Dont run anything out of the box. I bought my Stealths for $1000 and still had to have $450 worth of work.....recut seats....checking guides.....replacing retainers and locks. Now days with prices up to $1499 then having them corrected we are talking 2k for a set of Stealths, really?? I would see how much work the 915s will be or pay up for better heads like Trick Flows or Indys.