How to identify a 351C Cleveland.

The 351 Cleveland isnt a big block, medium block or a small block.

Ford never rated ther engines in small vs big block.

Ford named their engines in series like 335, 385.

A Ford 400 and 351M isnt a Cleveland.

There is no 400 Cleveland or 351 Modified Cleveland.

They are just 400 and 351M.

351C, 400 and 351M belongs to the 335 series engine family.

But 351C is a different block than the 400 and 351M.

Its like the Windsor series engine with 351W, 302, 289 etc.

The only engine called Windsor is the 351W.

The others is just 302, 289 etc.

Production years for the 335 series engine.

351C 1970-1974.

400 1970 -1974.

351M 1975-1982.

There is many ways to identify a Cleveland motor. But to determine if its a Closed chambers or open chambers there is only one correct way. Also to differentiate a 351M from a 351C can be tricky.

From time to time there is 400 and 351M engines for sale where the seller claiming it is a 351C.
Many times the seller dont have a clue and sometimes the seller is trying to scam you.
A 351C retails a much higher value and a novice or less careful buyer can be fooled.
Dont let it happen to you.

Read this and remember the differences and take a tape ruler with you to determine what engine it is.
Ask for casting numbers use the net to get facts of what it is.

The most desirable Clevelands is of course the Boss 351 1971 with the adjustable valve train and also the standard closed chamber heads 1969 to 1971.
Many also wants the 4 bolt main block which came 1971 and later (Boss and Cobra Jet).
So early heads and late block is the way. If you ask me the 4 bolt main is a overrated hype. 

The intake ports on a 351C 4V are HUGE!

351C upper radiator hose, intergrated timing cover, fuel pump.

The differences from 351 Windsor.
A cleveland have always:
The upper radiator hose to the block.
8 bolt valve covers/each.
Fuel pump bolts over and under pump.
Timing cover integrated to the block.

A 2V cleveland have a #2 in upper both corners of the cylinder head.
A 4V have the #4 in the upper both corners of the cylinder head.

If your heads is clevelandstyle but dont have the #2 or 4 its heads for the 400 or 351M.

They looks like 351C heads but is different with larger combustion chambers wich equals lower compression.

2V and 4V stands for the number of venturis not the number of valves.

#4 upper left corner 351C.

To tell which casting # the head have, you may have to pull them off the engine
or atleast the intake manifold.
Casting numbers is at the bottom off the cylinder head.
There is D0AE, D1AE, D1ZE, and D3ZE.
-73 (D3ZE) and up have smaller valves.

To determine if its a closed chamber 4V you can pull the valve cover and read the date code.
This isnt a exact ID, but if the date code is 9xx or 0xx you have closed chamber heads.
If its 1xx the possibility is less but still possible. 2xx no way.

Explanation date code for cleveland cylinder heads (example 9J9):

First: 9 indicates year 1969.
Second: indicates month here is J September,
A to M, A is Januar to M is December, the letter I is excluded in the id-system.

Third: indicates 9th day of the month,1 to 31.

9xx= 1969, closed chambers, DOAE-G/H/M/N/R
0xx= 1970, closed chambers, DOAE-G/H/M/N/R
1xx= 1971, open chambers (BOSS= Closed) D1ZE-B, D1AE-GA/ D1ZE-CB/DA/GA
2xx= 1972, open chambers, (BOSS= Closed) D2ZE-A
3xx=1973, open chambers, with 2V sized valves 2.04"/1,66" D3AE-G2B, D3ZE-AA

Above: This is just info about the 4V heads, not the 2V heads.

351C 4V D3ZE heads with the smaller valves.

Date code 351C head: 9J9 here it is decoded 1969 September 9:th.
My other head have 9M5: 1969 December 5:th.

Here is the casting # red arrows (under side)

My DOAE-heads
Picture taken under side cylinder head intake when Intake manifold is removed.

If you remove the intake manifold you can use your cellphone to take a pic under the cylinder head between the pushrods  at #2 from the front at driver side and at #3 from front at passenger side.

Open vs Closed chamber

The dot 4 rumor. From time to time you can read about someone claiming that the dot 4 is a indication of that it is a cylinder head with open chambers.
That rumor is not correct. The dot is not an indication of that at all. There is both open and closed chamber heads with dot 4.
What the dot 4 means noone have an explanation for.

Yes i know that there is articles and "experts" saying that the 4. dot is open chambers.

But how do theese so called journalists work, yepp they do copy paste and no real background check.
I have personally seen several 351C-4V with a dot which is for a fact closed chamber heads.
Its very hard to kill missleading "facts".
But if you read Cleveland-forums like 54network.com and 351c.net there is a lot of real facts from real people with hard hands on facts about everything regarding the 351 Cleveland.

Still not convinced about the DOT rumor?
Take a look at this youtubevideo and be convinced.
Here you can see with your own eyes a closed chamber head  with the DOT 4 : 

One reason to this misinformation about the DOT is that the majority of the 351C heads is made with a DOT and a majority of them is also open chambers.

351C block

351M/400 block, notice the  difference
from the 351C block to the left  rised thermostat
 housing and the wall behind the distributor.

To determine a C from M, meassure deck height is the best way. center of crank shaft to deck.
Deck is the surface where the cylinder head is bolted.
The thermostat housing is rised  abt. 1" and there is a "wall" abt. 1" tall behind the distributor, cylinder head deck is rised abt 1" also.
Deck heights:
351C = 9.206 in (233.8 mm)
351M/400 = 10.297 in (261.5 mm)

Also how deep the distributor surface is located below the intake is a clue.
The 400 and 351M intake manifolds are much wider (abt 2") than the 351c intake manifold.

351C vs 351M/400 from behind, different bellhousing patterns.
351C have "small bellhouse" pattern
351M/400 have "big bellhouse" pattern.
There is some rare 351M/400 blocks with dual bellhousing patterns

A 351M is a destroked 400  with a "351 Windsor style crank" and have longer stroke and larger 351W main bearings. 351M have less Horse Power (~150hp) than the 351C (~300hp).

Note: The Boss 302 also have 8 valve cover bolts and have threaded freezer caps in the block.
The Boss 302 heads also have water cooling jackets openend up (front and back) towards the intake manifold.

Hur identifierar man en 351 Cleveland, 351C, BOSS 351, 351M, 400, 351W, BOSS 302