didn't all pontiacs have guideplates and screw in studs? i think the #16 head is the one they put on all the later 350 and 455 engines. but i could be wrong. they were different from 350-455. dfferent valves and chamber sizes. different ports. too.either will bolt where the other was,but will not work right...i think...
i knew this about 2 and a half years ago when i had a 78 trans am.but i traded it for my nova, and now i forgot.
1971 Nova(looks like 69 camaro from underneath!)
355sb, vortec heads, HOT cam,T-10 tranny, 3.70 gears 16" IROC wheels