IMO I would have someone knowledgeable port the heads you have. You can get a pair of BBM heads, maybe Survival, other than that everything appears to be "out of stock", and the promise date keeps getting pushed farther out. I've been buying "used" stuff when I find it just to keep things moving along. I just tell people, " if you want it now, you will have to locate some thing used". Otherwise wait, and it could be a long wait.