351 CUBIC INCHES (CLEVELAND) 4B V8 Big Block or Small Block?

[MF508]

I have a Question about the 1970 new big-block 351 cid four barrel V8 with the canted valves and larger ports resemble the 429 cid V8.

Is this Engine considered a Big Block?

I have asked so many different mechanics and even recently
a MCCA Judge and the answer was yes. Because of the canted valves and larger ports it's considered a big block. Some people
say it's a small block as well so i'm trying to just get the correct
answer.

I have this engine in my mach 1 with the shaker hood and was just wondering what your thoughts were on this subject.

Thanks
Matt-

[HotRod]

Either 351, Windsor or Cleveland are small blocks. The Cleveland is a hi rpm motor like the 4 valve modulars. The Windsor is very torquey when comparing rpm ranges.

['70 Vert]

A 351 Cleveland is neither a big block or a small block.
It's not in the 390/429/460 family, either. It's a stand alone design that came out late in '69 and was in production 'till '74 I think.

"351M's and 400M's" were "modified Clevelands" used from '75 'till around 1980 and were basically low compression smog engines with different deck heights, heads and intakes than the original Clevelands. "M's" look identical to real Clevelands, but they are an entirely different animal.

"Boss" 302's were beefed up small block "Windsor" 302's with 4v (that's 4 (venturi)barrel, not 4 valve) Cleveland heads. The engines share the same bore size and head bolt pattern, so swapping heads between engine families was easy.

A Cleveland block is a Cleveland block. It doesn't share parts with any other engine family.
Clear as mud, right?

[Bill Hamilton]

(Does this answer sound familar, Matt )


A small block (maybe actually a "medium" block) as the 390/428 and 429/460 series are big blocks. The 351 Winsor is most diffenitly a "small block" as it is similar to a 289/302 block but just slightly taller.

The 351C does share some of it's design with the later 429 series so in that aspect it could be considered a small block as opposed to a big block.

I think the "old" guys will say small-block while the new guys will say big block .

[Azure]

The Clev has a small block bellhousing pattern. The heads also came on the 302 Boss.

I say small block

[MF508]

Ok thanks everyone I appreciate all the responces so far it's definitely an interesting topic. It's interesting to hear all the
comments about this engine.

Bill it does sound familiar with what you said. I have to agree with
70 vert it's kind of in the middle not a small block nor a big block
but it's definitely a decent motor that has lots of possibilities.

Thanks for the replies everyone keep them coming if
you have anymore to add.

Matt-

[RnJstel]

Cleveland is well, Cleveland.

Here is how I understand it, correct me if I am wrong.

For all intensive purposes its intermediate.

Big Block traditionally starts at FE family, 332-352-390-427-428.

Windsor is small 260-289-302-351W and that bizarre 221/4.2L I think from 79-80.

No disputing Lima’s FF family of 429-460

Those family lines are pretty clear. Then comes Cleveland family, its kind of inbred and the genetic pool is muddy.

I am no expert (unless blowing holes in the side of the blocks count) on Cleveland’s but, this is what I understand

First introduced in 69 as the Boss 302, Windsor block but what came to be know as Cleveland heads. The Cleveland head took its design and valvetrain from the FF family, albeit different.

The Cleveland then became its stand alone motor somewhere in mid 70 and as the Boss 351 in MY 71 and early 72 but not called boss, those stuck around until 74 in its pure style. Somewhere in 74 the 351-400M (modified) replaced the Cleveland. They were essentially the same motors except for differences in casting and valvetrain for emissions (this is where I get lost).

I think the last application was a 400M truck application somewhere in late 79.

And then there is that whole Australian Cleveland family.

Clear as mud. Maybe a Cleveland Nut is out there somewhere.

[BlueHorse]

I guess it is what you want it to be. I have a '71 Mach 1 with a 351c [4bbl] and the factory [assembly] manual to go with it. The 351c is listed under the "small block" section in the manual so there is no telling who classified it one way or the other.

[tallymach1]

It is a small block version of the 335 series engines (429, 460). It shares the canted valves of the 429/460 and the distributors will interchange between the two. After that the similarities end. I call it a small block, although most old timers refer to it as a mid-block.

[falcongtho3]

I'd have to go with mid-size myself. It's not like a Chevy where big and small block are cut and dry. The Winsor block has always been considered a small block, while there were more than one of what should be considered big blocks offered by Ford...

Which begs the question...what are our motors?

[03mach69mach]

Small Block Mod Motors with a high rev, big block horsepower attitude. Sorry, though they have the horsepower, there is no substitute for Cubic Inches when it comes to stump pulling torque like an old Ford FE 428 Cobra Jet! Also, If it gets around 10 miles to the gallon without a power adder, then it probably is a big block. BB suck gas.

Also, my vote is that the Cleveland is a small block.:THUMBSUP:

[Chaucer]

The Cleveland is a mid-block, not a small or big block.

[VenoM]

smallblocks include, 221, 225, 255, 260, 289, 302, and the 351. all of these are Windsor engines. a 351 cleveland is considered a mid-block. cleveland heads will go on a windsor block with modifications. next on the ford V8 lineup is the 351-400 midfield or modified as some call it. the 351M is a 351C with a half inch added on the deck hieght and a big block bellhousing. then we have the 400M which is the 351M with a 4.00 inch stroke instead of the 351C and 351M's 3.50 inch stroke. and the 351-400M have 351C heads with 2.04 intake and 1.67 exhaust valves. also the 289, 302, 351W, 351C, 351M, and 400M all share the same 4.002 bore, the strokes being 2.87, 3.00, 3.5 and 4.00 inches. then we have the FE blocks which are true bigblocks. these include the 352, 360, 390, 427 and 428. and also the mercury/lincoln 406, 410, 430 and 462. after the FE blocks comes the 385 series big blocks which include the 370, 429 and 460. and also the mercury/lincoln 432 and 461.

[TheWaterSkier]

Originally posted by falcongtho3
I'd have to go with mid-size myself. It's not like a Chevy where big and small block are cut and dry. The Winsor block has always been considered a small block, while there were more than one of what should be considered big blocks offered by Ford...

Which begs the question...what are our motors?

Actually, I think the Chevy 348/409 engine is very similar in this repect. Check this site out for instance, they have big block, small block, and W block (348/409) sections. I had a 327 and a 427 at the same time and my friends 348 engine sure looked like a mid-block to me...

[408coupe]

Just because a 351c is in a different class than a 351w it is by no means larger. It is a small block with the same stroke and bore sizes as a 351w BUT with a shorter deck height. It is hardly a big block or medium block. The 351w is a larger block than the 351c so where anyone gets big block from I have no idea!

[Sam04]

Originally posted by '70 Vert
A 351 Cleveland is neither a big block or a small block.
It's not in the 390/429/460 family, either. It's a stand alone design that came out late in '69 and was in production 'till '74 I think.

"351M's and 400M's" were "modified Clevelands" used from '75 'till around 1980 and were basically low compression smog engines with different deck heights, heads and intakes than the original Clevelands. "M's" look identical to real Clevelands, but they are an entirely different animal.

"Boss" 302's were beefed up small block "Windsor" 302's with 4v (that's 4 (venturi)barrel, not 4 valve) Cleveland heads. The engines share the same bore size and head bolt pattern, so swapping heads between engine families was easy.

A Cleveland block is a Cleveland block. It doesn't share parts with any other engine family.
Clear as mud, right?

This is all true, but the 351 Cleveland is usually referred to as a big block to distinguish it from the 351 Windsor which was unique and was considered a small block.:THUMBSUP:

[408coupe]

Originally posted by Sam04
This is all true, but the 351 Cleveland is usually referred to as a big block to distinguish it from the 351 Windsor which was unique and was considered a small block.:THUMBSUP:

thats just not true, I realize that some people DECIDED to call it a big block but it is simply a smallblock with a different design, thats all!

[Chaucer]

Originally posted by 408coupe
thats just not true, I realize that some people DECIDED to call it a big block but it is simply a smallblock with a different design, thats all!

Actually, it is true that the 351c was considered a big block engine. Now most people consider it a mid block engine because that engine block family doesnt fit into the small or big block hierachies.

[GaPonyFarm]

I'll throw my lot in with those that refer to the 351C as a mid-block. Most recent publications have also adopted that term for the 351C.

Since I own one, I can tell you it comes out of an engine compartment like a small block, but shoehorns back in like a big block!

One thing is for certain... the 351C is a Torque Monster!

[69redmach1]

I think the confusion lies in the fact that the 221-302 engine is actually a sub-small block. The 351W/351C is more the size of Chevy 350 which is considered a small block

[TerryJ]

Did anyone mention that the cleveland had a 4 bolt main.the windsor doesn't.....and weren't the Boss 302's sleeved down clevelands...?

[falcongtho3]

Sorry, the Boss 302 was a Winsor block with Cleveland heads and unique intake manifold. Small block, but what a small block!

[Sam04]

Originally posted by 69redmach1
I think the confusion lies in the fact that the 221-302 engine is actually a sub-small block. The 351W/351C is more the size of Chevy 350 which is considered a small block

That isn't really a reasonable comparison. With the exception of a few limited production Corvette motors, all Chevy V8's are based on either the small block (283, 302, 305, 327, 350, 400) or the big block (396, 402, 427, 454). Ford also had small blocks (289/302) and big blocks (390, 429 and 460), but they also made numerous unique engines that weren't based on either block. The 351W has more in common with the 289/302 but it has a taller deck to accommodate the longer stroke. The 351C, 351M and 400M are a unique family and only the heads can be installed on Ford small blocks, but you have to plug two coolant ports and use a special intake manifold. Nothing else is interchangeable. With a Chevy small block, you can literally start with a 283 and turn it into a 350 by boring it out and installing a 350 crank, connecting rods, and pistons. If you start with a 302 all you have to do is swap the internals. You cannot turn a 298 or 302 into anything else, you cannot convert a 351W to a 351C, and you cannot turn a 351C into a 429. Ford simply doesn't use as many interchangeable parts on their V8 engines...:THUMBSUP:

['70 Vert]

Originally posted by TerryJ
Did anyone mention that the cleveland had a 4 bolt main.the windsor doesn't.....and weren't the Boss 302's sleeved down clevelands...?

Only ultra high performance Clevelands had 4 bolt mains.
(Cobra Jets and Boss 351's)

The Boss 302 was a windsor small block that was adapted to use Cleveland heads. It was a one of a kind thing during '69 & '70.


Sam04 hit it right on the head.
A 351 Cleveland is a unique engine. It shares nothing with other Ford engine families except bore and stroke measurements.
There's no need to label it a "small block" or a "big block".

Since I'm a member of the baby boomer generation, I feel I'm qualified to argue on the subject!

[falcongtho3]

A 351 Cleveland is a unique engine. It shares nothing with other Ford engine families except bore and stroke measurements.
There's no need to label it a "small block" or a "big block".ANGEL: [/B]

I think you've hit it on the head! All my years a Cleveland was refered to as just that, a 'Cleveland'. A Winsor, the same thing. If you're a Chevy owner, I guess it's a requirement to keep things as simple and mentally un-challenging as possible, hence: big block or small block. This does not speak well for Pontiac owners either, as there is pretty much only one size block...