ford 351 w/c

Well, dmorris is right. The windsor family consists of the 260, 289, 302, and 351. This means that pretty much every part of the engines besides cylinder heads and intake manifold are interchangable. (depending on year) The 351 is in the same family as the 302 and others, meaning it uses the same parts, however, the block is just a little bit taller with a bigger deck height and main journals. Because it has a bigger block, it uses a wider intake manifold...but it looks the same. The heads would be identicle to all of them, except earlier 351 heads have bigger ports and valves, and all 351W heads use 1/2 inch head bolts whereas the 302 and other smaller windsors use 7/16. But it is possible to put 351 heads on a 302. But, you cant make a 351 with a 302 block. And also...as dmorris said, they are all inline valve arrangements. There are many interchangable parts in the windsor family, so many its hard to keep track of, (and yes, years do matter) you'd probably need somebody who knows a lot or buy the book.
..The cleveland however, is a big block. In 1970 if you bought a mustang with a 351, there is no real way you could specify if it came with a cleveland or a windsor. It just depended if it came from the ontario plant or the cleveland plant. Because it is a big block it has bigger ports and valves with the canted arrangement. 351c's are good engines, i read the the 351 cleveland makes more power per cubic inch than any other gasoline american made v8 engine. I just dont know why they arent more popular. You cannot interchange 351 cleveland motor parts with any 351 windsor motor parts. Back in the day, clevland heads were the thing to have, now, you can just buy some aluminum race heads that outflow the clevelands and put them on the more popular windsor block (which is what most people do)
The 351m stands for 351 modified. It is basically, a modified 351c. Im not sure if you can interchange 351m/351c parts. They also made a 400m, wich is the same family as a 351m. These engines were usually put into trucks and i dont think were very good for performance use....i coud be wrong so dont take my word for it.
well thats what i have to say about that... hope i helped a little

hey guys i have a 351c with many 351m&400m parts for her im putting her in a 80 f100 p/u when i had the old 351c it was neet to see the 50s go down the drain my son had it in a rich neighborhood one boy looked over and saw a p/u and said hey country boy want a city boy to show you how to run my son has a short temper and told the kid first to next light when they took off my son thought he had lost it he said dad i was going to beat him or blow it up he ran it up to 6500rpms when he shifted into secound thats all she wrote for the 50 at the next light the 50 pulled in behind him my son with his long temper put his truck in park went to the 50 & told the kid if he wanted to come to the country & we would show him how to run that 50 the guys girlfriend said finaly got beat and by a country boy on top of it for this reason ill stay with my 351c may take more time but ill have fun & a family truck also cheap on gas gordo

one more time ford 221,260,289,302,351 Windsor engines are manufactured in windsor ontario canada these are in effect ford smallblocks good engines with a superb oiling system and poor cylinder head ports every thing will interchange with the exception of the 351w crank journals are larger the block is a half inch taller and bolt are larger intake manifolds are wider camshafts had different fireing order in earlier models but cams will interchange provided you use the correct order for that cam oil pans are different boss302 351C and 351m and 400s are made in cleveland ohio all cylinder heads will interchange the oil system is weak the cblock is smaller and lighter pistons between 351c and the 400 interchange but the 351m won't(yes the 351m is 351 cid)intake manifolds between the C and M won't swap but cams oilpumps time gears(not chains)exhaust manifolds will cranks won't rods no trannys won't between C and M trannys between the 429/460 fit the 351m400s trannys for windsors fit the 351C, then there are hybrids called clevors and strokers where certain parts of different engine familys are combined to make somthing different from what ford offered