supposedly someone in japan is making a aftermarket bolt on kit for nissan sr20 engines, i know this can be adapted to 3sgte's and 4age's, it would be interesting to mount up the small port 4age's head to a b-16 block and see what happens, although the motor do turn in different directions, im not sure how this would affect it( plus the fact the plumbing would be all wrong...but still...in theory...a toyota atlantic head on a 12:?:1 compression motor would be crazy rev happy)