manual valve body ??? I think

i think 70aar nailed it perfectly. i sell performance auto parts for a living, i've never seen a full manual valve body with the provision to hook up the kickdown linkage. the keyway knob that sticks up isn't even manufactured on a manual valve body. now they do market manual/automatic valve bodies. these will have it. but they are supposed to be held in gear for racing, but act normally in drive, still not the issue you're describing. i'd say something is out of whack and it's not a full manual valve body.