i am confused on the diference between the 351m the 351w and the 351c and can anyone explain the diferences to me?


ok i sound like a newb...and i feel like one now

 

351 and 400M's were made to replace the old 352-428FE engines. They were modified car engines made to work in a truck. 351C's are ok, but the one thing that was good on them were the heads when used on a 302 block making a 302 Boss. 351W's were made in Windsor Ontario Canada I believe and they are true truck engines solely designed for use in trucks. Of the three, I prefer a 351W for a truck and it's also the most common of the three after 1982. 351M's were used from 77 or 78 until 1982 when they were replaced by the 351W.

 

I don't mean to contradict anyone, but 351Ws started in (I believe) 1969. They were offered, I know for sure, in cars. I don't know what year they were offered in trucks (maybe 1969). They were not solely truck engines. 351Ws are essentially 302s with a taller deck height & a longer stroke. 351Cs are a completely different block. In my opinion, 351Cs are the best power to gas mileage engines Ford ever produced. 400Ms (like 302s vs. 351Ws) are 351Cs with a taller deck height & longer stroke. They also have a different bellhousing bolt pattern. 351Ms are destroked 400Ms. I understand this was done for emissions standards. My experience with 351Ms is that they are low-power gas-guzzlers. I once read a magazine article that said there was no good reason to build a 351M. I hope this helps clarify some of your questions.

 

351W is nothing more than small block with more stroke. It is the same design first used in 1963 as a car engine. The 351C is/was Ford high performance engine and may still be the engine they run in NasCar it is the most efficient of the these engines. The 351MC is an very poor example of an engine, low compression, low power, no gas mileage version of the canted valve engines and a 400MC is just big brother with all the same faults. A 351C is rare find these days and worth hanging onto when they are found. 351W's are good every day drivers with good life expectancy and can be made to make some decent HP with some head work and a good cam. There Cranks are very strong a lot more substantial than a 302.

 

okay that clears alot up thanks

 

so i slap some cleveland heads on my 302, then it becomes a Boss 302??

 

i think theres more than just slapping on cleveland heads on a 302 to making it a boss, the boss is fords version of the hemi. isnt there a 351 boss that is a cleveland?

 

[QUOTE=The 351C is/was Ford high performance engine and may still be the engine they run in NasCar

they run 358's in nascar

 

This is from the March issue of Muscle Car Review, page 46: 351 Cleveland 4V heads, since size and bore were compatible, were stuffed onto the 302 block and presto change-o, the Boss 302.

 

There are water passage issues that have to be resolved. I'm not sure what, exactly, but I know it requires either machining or a special intake. There is a company (I don't know the name) that makes a "Clevor" (Cleveland + Windsor) intake for mating 351C heads to a 351W, but I don't know about the 302.

 

The 351C is a high performance replacement for the 351W unfortunately it was too high performance and costly to produce compared to the 351W. The 351C block was blown up to a tall deck height to produce the 400 (no M, letter designations were only used on the 351's), with the 351C-2V heads. The 400 was intended to be a long stroke torque engine for use in large cars and even trucks. Ford succeeded and the 1971 model was a tire burner. Unfortunately the EPA regulations killed the motor and in 1972 it was smogged to death. The 400 was used in trucks starting in 1977.5. The 351M is a de-stroked 400 with tall heavy pistons and has never been any kind of performance engine. The 351M was produced when Ford could not make enough 351 size engines in their existing plants.

A history of the 335 series engines can be found here:
https://www.ford-trucks.com/article/...00_Engine.html

Clevor parts are scarce and there are better options now for a high performance 351W engine, see the 351W forum. The Clevor is a 351W with the very free breathing 351C-4V heads that is suitable for racing applications only. People also used the 351C-2V heads since they were a big improvement over the stock 351W heads.

The 351W is a tall deck 302 and has some very restrictive heads. There are high performance head options for the 351W now.

The 351C was produced in two basic versions with either the 2V heads or the 4V heads. The 2V heads were small compared to the 4V heads but they breathe very well which is why people with 351W tried to bolt them on their "wheezers". The 351C 4V head version did not work well on the street and should only be used in high RPM racing applications.

The 351M is a de-stroked 400.

 

In reply to size_matters_460 Nascar's max engine size is 360 ci And every one runs real close to that number to make a 351 a 358 you either increase the bore about .040 or the stroke by .080 and the block is the only thing they use the rest is strictly race stuff.

 

The head design on the nascar motors is based off the clevelands (they used the 4V quench heads in the busch grand national series for a long time in the 70's).

The 400's are a very strong motor and they are torque monsters (one of the longest strokes of any ford motor), and when built right they can make very serious power (a guy in the 335series forum has a 800hp 400 in a pulling truck). I have a 400 in my 81 competition bogger, and with the few mods i'm going to do to it (clevland 4V quench heads, a comp cams K kit, intake spacers to use a cleveland torker intake, headers and a nice big carb to feed it all) it will be pushing over 400hp, if one ever does build a 351M its best to just throw in a 400 crank and rods to get the benifit from the extra stroke.

 

If I'm not mistaken, the only difference between the 351M & 400 is the crank & rods, so this would actually make a 400. Am I right?

 

yeah,that's the only major difference.there is however a difference in the water distribution however.it changes a bit due to the changes of internal parts in the motor.