Efi magnum swap

We build both, depending on customers needs. I would guess 6-8 OBD II for every OBD I. We have two company's that flash for us . I believe one of them works with OBD I. If you plan on using larger heads and cam, I would stick with OBD II . There are a few more things for OBD II but not tons. You can get a bunch of HP out of both.