I have a set of those '92/early 93 mag ex manis & they are streamlined & have a ~2&1/4" outlet as opposed to the 1&7/8" on the later ones, quite a diff & ex for the flange size they look identical (casting # may be diff). I too am doing a 302 build (318) & thinking going from 1.78" to 1.88 valves per advice (on here)