How to identify SB Ford heads without pulling them

The first thing you have to do is pull a valve cover and look for displacment casting number. Ford was pretty good about casting displacment numbers, but they didn't do it on all engines. There will be two pre 77 engines that Ford did not do this on. The engines will be the 221, 260. The rest of the pre 1977 SB Ford engines will have a 289, 302 and 351 cast on the top of the head under the valve cover. Post 77 engines did not cast dispacment numbers only casting number on the deck side. Now that is the easy part, so what if you want to know what year of 289, 302 or 351W head you have or if you have 221, 260 or 255 heads.Use your visual clues to identify what head you have. First off, if you have a head with no casting displacment number on it, then it must be a 221, 260 or a post 77 255, 302, 351W head. So which one do you have, look at the rocker arm. If you have a conventional rocker arm with a machined slot in the head for a push rod, you have a 221 or a 260 head. If the head has a bolt down sled fulcrum, with a large hole drilled for the pushrod, then it is a post 1977 255, 302, 351W head. Next, Ford used two different rocker arms setups for the 289, 302, and 351W and one rocker arm design for the 255. The 289 used a conventional rocker and a rail type of rocker arm. The 302, 351w used a rail rocker arm and a bolt down sled fulcrum. The 255 used only the bolt down sled fulcrum type of rocker arm. The 289 used the conventional rocker arm up to mid 1966 and then switched to the rail rocker arm design. So if you pull a valve cover and it says 289 and has a conventional rocker arm it is a pre 67 head. If it has 289 under the valve cover and it has rail rockers it is a 1967-68 289 head. Now that was easy, lets try something harder like a 302 head. If you pull the valve cover and it has 302 then it is a 302, but what year is it. Ford used two designs of rockers for the 302, rail and sled fulcrum. If you have a 302 with rail rocker arms it is a 1968-1977 head. If you have a head with no displacement casting numbers and bolt down sled fulcrum rockers then you have a post 77 255,302, 351W head. The 351W will follow the same basic rules as the 302. So what is the exact year for 302's and 351W's  without having the exact casting numbers. The 302's are the tricky ones, so here is how to look for visual clues. In 1968 Ford used adjustable rail rockers on 302's, the rest were non adjustable. How do you tell if you have a 1968 302, look at the rocker arm studs. If the stud is not shanked down at the threads it is a 68 302 head. In 1969 Ford changed rocker studs to a non adjustable set up, the stud thread will be shanked down. The post 68 302 will also use a smaller rocker retaining nut than the 1968 302 head. So if you have a shanked down stud and rail rockers on your 302, it is a 1969-1977 head. This is close but not close enough, so how do you narrow it down? Again use visual clues, to determine what year of head you have. In 1975 Ford went to internal smog ports on the the SB heads with a tube connecting both heads together going to the smog pump. So if you have a 302 casting numerber with rail rockers and tubes on the back of the heads connecting them together, you have a 1975-1977 302 head. The 351W is quite a bit easier, but the 351W has some quirks. If it says 351 on the top of the head below the valve cover and has rail rocker arms it is a 1969-1977 351w head. The 1969-1977 351W head will use 16 intake manifold bolts as opposed to 12 for the 221, 260, 289, 302 and 255. In 1978 Ford made both 302 and 351W head interchangable with no displacement numbers cast on them.The last part is how to determine a 255 from the 302 and 351W head. The 255 will use small oval ports as opposed to the rectangular ports of the 302-351W. The only way is to pull either the intake or a exhaust manifold. If it has oval ports its a 255, rectangular 320-351W.