351 Cleveland 400 or 351M Which Is It?

[@mitchf1508]

I had a 71 LTD with the 400 in it. I was 16 years old, so I tested it's WOT ability from a stop all the way to burying the 120 mph speedo a few times... 😎 This was back in the late 70's. I had that car until around 1985 or so. I "refreshed" the 400 around 1983. I did it with the block still in the car. I replaced all the main and rod bearings and the rings on the original pistons. There was no cylinder ridge, so I just gave it a quick "hone" with a rented honing stone from the parts store. For the heads, I had them gone thru by a shop with new seals and what was considered a basic "valve job" of the time. I replaced the cam and lifters with a Comp Cams "RV" style came. It was meant for lower rpms, but gave it some more low end torque which was fine because I had to keep the 2bbl manifold/carb due to $$. I put a dual exhaust on it too and that gave it the V8 rumble you wanted as a kid! Over all a fun car and held it's own from a stop light.. 🤪 I wanted to get a 429 or 460 for it, but I had to get rid of it due to $$ and moving on with life, but it's always been one I wish I had kept.

[@hotrodray6802]

🔔😎 Being a Ford mech back then, we referred to the C as a small block, and the M/400 as big blocks, as per mounts and bellhousings.

[@gregoryplummer-l9l]

I went to an estate sale on a farm and thair was a Cleveland short block and a pair of heads with a 4 on each corner they wonted 100 for the head's And I asked about the block I figured that the head's at one time came off the short block thay wonted 300; for it I told them 3 old lady's and one younger one and she seems mouthy thay wonted me to buy it all and I said I would buy the head's but mouthy mead me up set and I in just said thanks anyway and started to walk away the oldest woman said you didn't want me heads I said I was interested but she made me feal like don't know what I'm talking about and I have rebuilt more engines than she can count the told mouthy to get lost and asked me what I would pay she just wanted it gone so didn't have to hail to the dump so I said it's got to be rebuilt that's a lot of money and I can't tell if it's any good she said 200 for heads and block so at that price was fair and I bought them took the pan off to see if it had thrown a rod and found out it lts a 4 bolt main ferther checking it's standerd bore and it's numbers match the head's wail we were loading it I found the 4bb.intake manifold and exzost manifolds and a stick flywheel and a starter got e all except the carb it was probably already sold good prices for a 4 bolt block I didn't take the pan off until I got home

[@MrPoppyDuck]

Wow 50 bucks for a pair of 4 bbl 351c closed chamber heads? That is basically free! Nice score!

[@hotrodray6802]

YeeeHaaaaw!!!

[@mycontinental3611]

Jeff I also seen them being called 351 Midland 400. Great info. Back in my machine shop dayd I used charge $100.00 per sleave.

[@JohnDoe-pv2iu]

I paid $125 for a sleeve in Augusta Georgia around 1998. K&P MACHINE was an Augusta shoo that i haven't been to in years. If they're still around, you really couldn't hardly beat them for great work that was reasonably priced. Also Carolina machine or (later)Caroline Machine Engines was also a Top Notch shop in Johnston SC. I used those when I lived in Belvedere, SC. Now, living south of Augusta, I use Hendricks in Statesboro (pretty inexpensive) and Bill Ford( Not as inexpensive 😂) of Screven county, GA. I should say here that I only use shops for boring now. I have a milling machine, Lathe, vertical boring machine, valve grinding machine(and seat/guide cutter) and Magnaflux rig. I do magnaflux and rebuild heads very inexpensively in Burke County, GA. I was told many years ago that Ford used a term (like the Russian and other people of various parts of the world)in manufacturing that was a popular 'buzz word' of that time. MODERNIZED... It seems that in manufacturing of the 60s and 70s, it was hip to have Modernized your old crap. So, like Russia's stamped rifle being called AKM for Modernized AK. The 351M was the Modernized 351. It was probably never in print because, while the term was Cool in manufacturing, it probably would have been looked down on during the Cold War, to call it "Modernized" in America! I guess everyone heard something different but I tend to believe that a "New and Fancy Buzz word" of an era could very well be what they called it! Yall Take Care! -John

[@lilhoss45acp75]

We ran a machine shop for 40 + years, they were all 351/400 Midlands!

[@johnnycapan6566]

As ford needed a replacement during the 70s for the FE. The M designated term was applied because there master parts catalogue had 3X diffrent 351 families... For me M most likely modified 351 of the 400. Reinforced rib , 385 series bell housing and 3" mains journal.. Got one myself will plan going the Tim meyer inspiration build.. 5 speed manual.

[@MFE92]

There was no Ford plant in Midland and there wasn't a 351 plant in Michigan. 351's were from Windsor, ON (canada) or the very different 351 Cleveland from Ohio. So the M did not stand for Midland or Michigan. It stood for Modified, as in 351 Modified, as in, a 400 design that was modified to 351 cubic inches. That's why you see 400/351M in so many parts listings.

[@projectmayhembronco5457]

I agree that the M stands for modified, and the master parts catalog back that up, but Ford did indeed have make the 351m at both the Michigan Casting Center in Flat Rock Michigan, and at the Cleveland Foundry.

[@blakeneysanders4264]

Good information Jeff. Thanks

[@HeathKopp]

Double valve springs with a dampener spring there Jeff...

[@HeathKopp]

There were a few 400 blocks that were made that had a dual pattern bellhousing machined from the factory....for either the sbf or 385 series bellhousings.

[@waynepaul9276]

@heathkopp. Please elaborate. It’s been documented that the very early 400 blocks were cast with small block bell housing patterns and the smaller pilot hub size then were subsequently changed to match the big blocks. Dual patterns? That’s new to me and I’m interested in hearing more details

[@JohnDoe-pv2iu]

I've seen a dual pattern bell housing. It scared the Hell out of me. I thought somebodies 1911 went full auto to make all those holes!!! Ford made a lot of crazy stuff in very small lots. I wouldn't doubt the block but GOOD LUCK finding one! Yall Take care. John

[@2dooroldford]

Even though 400 isn't "m" to find parts it is best to use 400m as if you just use 400 you will get gm stuff mostly, however typing 400m, will bring up correct ford stuff instantly

[@socalltd]

Correct, 71-74 400's were just that and from 75 up, the 400M was listed for both 351/400 displacements for service items.

[@JohnDoe-pv2iu]

Do you guys know anything about the 351c, 351m.and 400 replacement head? Ford made a single replacement head that was for all three. Are they a decent replacement for 351c 2V heads? Thanks, John

[@psychoholicslag4801]

Look for the rib. No need to measure to tell the difference between 400/351M and Cleveland blocks. Ford only ever called it Modified because it was not a 400 which was never called an M. It was referred to as Modified because it was a 400 block with a crank and pistons Modified to be a 351 instead of a 400 and to distinguish it from the Windsor in parts and reference literature. I have a pair of actual 351M, with the M cast on the corner of the, heads. They were usually put on warranty work engines and have revised coolant jackets around the exhaust valve in the port. All shop manuals and advertising I've seen only ever called it Modified.

[@OlysGarage]

Can't say I've heard them called Michigans, but definitely Modifieds or Midlands. The story as I've heard it was the 351M got the 'modified' designation because it was a "modified" 400. Also, for some strange reason in either 71 or '73, there were 400s made with dual bell housing bold patterns, both BBF and SBF.

[@stephenhotzjustdriveit]

The fun details

[@daledavies2334]

Then just to confuse the uninnitiated, there was the 351M GMC V6.

[@chrisrye9128]

Race prepped CC heads for only $50?! Stole 'em! Nice find!

[@hughphillips67Mustang]

Related topic, in my family, there have been knock down drag out arguments, in fact, has caused permanent divisions between family members, over the 352 FE engines. I've owned engines that the block was stamped 352, but was a 390 engine. I've had engines stamped 352, that were 352. But had the older generations in my family tell me the stamps said what the engines are. (I'm 52). I tried to stand my ground and explain certain engine blocks in a certain time frame, all used 352 engine blocks. But we're different c.i. engines. This has honestly drove a big divide in my family to the point we haven't talked for years over it. So, there are a lot of subtle differences in engines. If you don't know what to look for, or do your homework, it can be confusing and misleading. And in my case, cause major issues personally.

[@hotrodray6802]

Most all FE had 352 cast in the block. I had a CJ with 352 cast on the drivers front. But not 427s.

[@hughphillips67Mustang]

@hotrodray6802 my point exactly

[@et76039]

I knew of one guy who thought he had a 390 in his '68 Ford, then pulled the engine when someone claimed it was actually a 352. Since 1967 was the last year for a 352, he had probably been misled in the manner described here.

[@hughphillips67Mustang]

@et76039 the only true way to know if it's a 352, or a 390, is to measure the stroke. There really is not a sure way to know just from looking. In the guys case your referring to, it's always possible the engine had been swapped out at some point. This was the case in my 65 f-100's I had.

[@et76039]

@@hughphillips67Mustang, agree that measuring the stroke is the best way to differentiate. An engine swap in that 1968 car is a possible explanation, but low likelihood. I do recall the 352 as an option in mid-'60s Ford pickups; not sure when it was dropped in favor of the 360. Trying to keep the facts straight on Ford V8 engines is a challenge.

[@projectmayhembronco5457]

The Ford master parts catalog refer to the 351 M as a 351 modified.

[@jdedmnds1]

The 400 M had a habit of bending push rods. I think it was due to valve guides sticking to the valves. A 400 M with 351 M heads is a good engine.

[@fordman4287]

Couple hundred bucks for a sleeve and .30 over (that's what my FE cost me to do), which is what you may end up having to do with a replacement block anyway.

[@GeekGinger]

It's strange, because my first car was a 72 Gran Torino with a 351W and C6 combo (which is weird enough) but the 351W was deceased and mechanical know-nothing 16 year old me put in a 400 from a station wagon but as I remember I kept the original C6. I've read many things that say that's not possible and now you corroborate that. I'm sure you're right so I'm wondering what I did way, way back then. It's strange how memory does/doesn't work 😁

[@vrm86gt]

the C6 was available with small block Windsor and big block bell housing so you probably swapped engine and also swapped in the C6 that came with the 400 with it since your car was already setup for C6 that would make sense.

[@DominatorGarage]

The early 400’s were both small and big block pattern could’ve had both.

[@hotrodray6802]

​@@DominatorGarage A few, yes.

[@vrm86gt]

@@DominatorGarage well that would make sense also

[@socalltd]

@@DominatorGarage I have seen late 70's T-birds with both 351M/FMX and 351M /C6 in them in the yards. It's true that some early 400's had a few FMX's behind them.

[@DominatorGarage]

Have the cylinders sleeved sir. That’s what everyone does now on clevelands

[@sonnymiller1486]

If you can save it, Save It!!!! This getting rarer and more costly everyday.

[@JohnDoe-pv2iu]

And save them all(not just rare)! Whats plentiful today will go away. And that will suck even worse if the replacement is electric!!!!!

[@chuck_machine]

Just sleeve #5. Sleeves run $150/ea in California, I imagine it's probably cheaper where you are.

[@4thGloryMonday]

ever hear of the 351m referred to as the windsor?

[@hotrodray6802]

Nope, but in the 70s we referred to the C as a small block, and the M as a big block... Mounts and bellhousings.

[@jdedmnds1]

351 M had soft cranks and they would eat bearings very fast. If you want to build a 351 M you need to get an aftermarket crank, otherwise they are garbage.

[@Ford_Falcon]

Im aussie here its 302 or 351 how tell them apart 351 distributor goes into intake manifold and 302 distributor goes into block and how tell if cleveland or windsor is rocker cover/valve cover 1 is 8 bolt 1 is 6 bolt also shape cover 1 square 1 isnt

[@hotrodray6802]

M, 400, 429,460 use the same distributor.

[@johnnycapan6566]

Only FE Motors go through the intake manifold.. not windsor or clevo. You're thinking of thermostat water running through the windsors intake.

[@johnhenry1395]

Thanks!

[@joshuahabeger-jj9cp]

I believe that neither the 351m or 400 came in 4 barrel. If someone could confirm that for me, that would be great. I'm a FE guy 335s and 385s are a mystery to me. Thanks in advance.

[@vrm86gt]

i think your right pretty sure they were all 2 bbl

[@normanchristensen783]

I believe the police issue was a 4 barrel

[@hotrodray6802]

There were some 4bbl. My friend bought new a 4wd F150 short box that had a 400/4 bbl. New. Only one that I've ever seen.

[@vrm86gt]

@@hotrodray6802 nice, probably pretty rare too.

[@vrm86gt]

@@normanchristensen783 didnt know there was a Police 400, going to check that out.

[@fomoco85]

351 midland

[@projectmayhembronco5457]

according to the Ford master parts catalog it a 351 modified.

[@normanchristensen783]

The Marti reports list the modified engines as Cleveland’s so this is very confusing to the hard headed ones!!!

[@hotrodray6802]

Remember, that when the C ceased production the M came in. They were not simultaneous.

[@normanchristensen783]

@ true one ended the other started so what was your point? My point was the marti kept saying it was a Cleveland after 74

[@chrisjarvis4449]

m for midland

[@glennramsey917]

I have a 1972 351c bottom end thats rusted cankered n stuck with some 2v 1972 heads id sell if anybody wants it