[updated:LAST EDITED ON 30-Jun-02 AT 02:45 AM (EST)]i have a true 400m in my truck and was wandering if it is a small block. by the way i dont care what the m stands for.

 

No. The bellhousing is the same as the 385 bb's. The rest of the engine shares it's design with the 351M

 

[updated:LAST EDITED ON 30-Jun-02 AT 09:57 AM (EST)]>i have a true 400m in my truck and was wandering if it is a
>small block. by the way i dont care what the m stands
>for.

Not again - this thread comes around on a regular basis! Small block/big block is mostly a Chevy thing, although the 289/302/351W are often considered small blocks while the 352/390/428/429/460 are considered big block (I may be missing some family members here - don't bother telling me).

The 335 engine family - which does not include a 335 - is comprised of the 351C (and variants Boss, CJ, HO), 400 and the 351M, which is a de-stroked 400. They are not small blocks or big blocks - perhaps mid-blocks. The 351C shares the same bell housing pattern as the small blocks, while the 351M/400 share the bell housing pattern of a big block. I would not categorize them as small block or big block based only on the bell housing pattern, mostly because you would be breaking up the family. If forced to decide small or big, I would point out that a number of parts are shared with both families but more are shared with the 429/460. Also, the heads are similar to the 429/460.

Lastly, you do not have a 400M. You have a 400. Only the 351M officially carried the M designation and pondering the meaning of the M will lead to more debate between Modified/Mid/Midland/etc ad nauseum. Someone will certainly be compelled to post that their 23rd cousin who invented the 400 calls it a 400M...

 

At 575 lbs, I consider my 400 a big block. Regardless of technical clasification. My engine stand also says its a big block by the way it flexes when the 400 is on it. (and I even have an aluminum intake).

 

Another consideration: All 335-series engines (351C/351M/400) have the same bore size (4.0") and bore spacing (4.38") as 289/302/351W small blocks.

Since the original engine in the family (351C) had the same bore size, bore spacing, and bell housing bolt pattern as the existing Windsor-class small-block engines, it was generally considered a "small block" engine as well.

Also, all the 335-series engines are smaller and lighter than the two engine families generally referred to as "big blocks," the 352/360/390/428 FE engines, and the 429/460 385-series engines.

 

In my opinon The terms big block and small block are not rellevent to for engines and shouldn't be used.
Then again I also think we shouldn't call our LSD's "Posi" either.



1970 Mustang Grabber Sposrtsroof. Rather non-stock...
1965 f100
2000 Focus Wagon

 

heh he, lets see the 335 engine family. its bigger than a small block, smaller than a big block. this comment has no real redeaming valve, out side of what it states. most people consider it in the "small block" grouping, I call it a mid size block.

 

If you are competing in a racing classification that allows only small blocks, it works to your advantage. It also gets the Chevy guys upset when they lose.

It weighs almost the same as a BB Chevy. About 150 lb. lighter than a 332 FE big block. The height and width are almost the same as the 460.

This is one of those questions that I answer "who cares". Why do we have only 2 ways to describe an engine. How about smallest, smaller, small, medium, big, bigger, biggest.

 

[updated:LAST EDITED ON 01-Jul-02 AT 06:22 AM (EST)]I was at the digs today and this topic came up within the group of strange numb-nuts I run with. One of our group just bought himslef an $22,000 454 cid "small block" chevy. This engine doesn't have one chevy part in it.

The block is from oldsmobile, the heads are pontiac, the crank and rods are Crower, and so on. NHRA and IHRA do not really call any engine a small block or big block, they just look at the cubic inches vs. weight ratio. I can't see a reason to honestly lable an engine one way or the other.

The only Manufacturer that I know of that called their range of engines "big/small blocks" was GM. I don't recall ever seeing or hearing a ford/chrylser ad talking about "big blocks".

 

This topic kills me. It is like asking what is a 350 Buick or what is a 350 Pontiac (sorry about the GM info)? Big Block or Small Block? Well all BOP engines share simillar engine blocks where only the cubic inches and cylinder wall thickness are different between the 350's and 455's. As for Chrysler, is a 383/400 a big block? The "B" series engines are shorter than the "RB" 426/440. If you have to classify the 400 for a racing class, call it a small block and watch the stroker Chevy guys cry.

As for the M, from 1971-1974 the 400 was a 400 in ALL of Fords books. It wasn't until the 351C died off and the 351M was introduced that everyone had problem calling the 400 a 400 and not tacking on the M.

 

Actually, the 351M and 400 heads are exactly the same as the 351C 2 Bbl heads.

 

Not exactly according to Kenny Moore.

It's widely claimed (even by Ford!) that the 351M and 400 use 2V Cleveland heads, it's not true. The 2V head has a nice smooth exhaust port. The M head has a "potbelly" port you can barely get your finger through, with the water jacket drooped down around the valve guide. You can't grind the potbelly out because there's water inside it.

 

All of the ford guys now that ford engines are all to difernt to clasify into two grops but this is how i descibe it to chevy peaple.

Ford guys have the small blocks the clevelands and the big blocks. The small blocks are the 289/302/351W the cleavelans are the 351/400 and the big blocks are 429/460/FE. The 351C is like a small block wanting to be a big block and the 400 is a big block wanting to be a small block. They are in a leage of there own.

-Jim

 

Who gives a crap if it is a small block or a big block? I have always been taught that SB and BB were pretty much chevy exclusive because all small block parts fit all small block engines. Same with the big blocks. As for ford - There are the windsors, the clevelands, the FE's, and the 385's. I will admit that most people refer to the windsors as the small blocks and the 385's as the big blocks. But I have never heard the Clevos or the FE's referred to as anything but those names. You can't classify them because the FE was a totally different engine and the Clevos borrowed parts from both the Windsors and 385's. I think that SB and BB are chevy terms and we should just call the Ford blocks by their names. If Ford had wanted them to be called small block and big block, there would be Small Block Fords and Big Block Fords, not windsor and 385. So if you are looking for a definite answer, you aren't going to find it. One other interesting side note to add fuel to the fire. I would call it a big block personally because the 400 has the longest stroke of any ford V8 pushrod engine, with the exception of the new "modular" engines. And if you want to know what those engines are classified as - they are modulars. Not small block or big block.