Jay is no longer with us, but, I believe the answer is that it's a vertically mounted filter for GM applications that's mounted next to the oil pan that really doesn't NEED an ADBV, but (as in all oil filters) one doesn't hurt anything. The 6.2 GM diesel in my sig uses a PH/TG/XG2, a common SBC (& other GM) size. It doesn't have an ADBV, but I've seen other oil filters for it that have one.