Here's the situation....

I have a '79 F100 with VIN code H, 351 engine. The person that owned it before me said it was a 351C. I wrote that off, knowing C's didn't come in F series. I figured it was an M, no big deal.

As I look at it, though, it gets confusing. There is an A/C mounting plate (what the compressor would bolt to) on this engine but the truck clearly has never had a/c. So not the original engine. If I understand correctly, the only way to tell an M from a 400 is the crank and pistons. How do you tell a C from an M ? The engine is installed and runs great so I'm not gonna tear it down any time soon, but I'd like to know what I have and where it came from.

I know there's supposed to be a casting # somewhere, but not sure where it is or how to go about breaking it down once I find it. Any help would be appreciated.

Thanks

 

Hi,

I don't know how to tell the two apart, you need to hear from bill_beyer, he will know for sure. What he says you can pretty much take to the bank.

-Brents.

 

Casting codes for the 335 series are under the right bank of cylinders. 351M/400 blocks are a little over an inch taller than the Cleveland blocks. Usually this means that there is a ridge about a 1/2" wide and an inch tall that runs parallel to the centerline of the engine next to the distributor on the block. I've heard that some folks have seen M blocks without them tho' so there's no guarantee. Another thing to look for is a number or letter cast into the front corner of the head next to the intake. A "2" or "4" indicates a Cleveland head, an "M" or blank spot would indicate a 351M or 400. But if this is a rebuilt motor then the heads could have been swapped too.

Best bet is the block casting codes if you can scrape away enough crud and get to them. A D0 or D2 would definitely be a Cleveland. D1, D4, D5, D7 or D8 should be a M. A D3 would be a 400 FMX block.

 

Told ya

-Brents

 

Thanks, Bill.

Looks like it's an M. Casting code is: D1AE 6015 A2G
I also found the "ridge" you referred to next to the distributor.

Is there any way to break down that code to find out what the engine came out of? I suspect it's another late 70's truck but it would be nice to verify.

Thanks again.

-Ed

 

>Thanks, Bill.
>
>Looks like it's an M. Casting code is: D1AE 6015 A2G
>I also found the "ridge" you referred to next to the
>distributor.
>
>Is there any way to break down that code to find out what
>the engine came out of? I suspect it's another late 70's
>truck but it would be nice to verify.

Hard to say for sure. It's a '71 casting so I'd suspect it's not from a late '70s vehicle. The 'A' stands for full size car but that's not necessarily a guarantee either tho' if I were going to bet on it I'd say it probably came out of an early to mid '70s car. Considering it is such an early casting date I might even suspect it's a 400.

 

I had a 73 351c and it had an aluminum tag under one of the bolts in the intake manifold right around the dist area. It had 73 351c right on it. I wonder if they put these on the later 351m/400's too.

 

Ok, I did a little more research on casting codes. Not finished yet, but what I have so far....

D1AE 6015 A2G
Correct me if I'm wrong, but it breaks down as:
D1 = 71 (Casting Year or design year)
A = Galaxie Car line(O=Fairlane/Torino, S=Thunderbird, T=Truck, etc.
E = Engine

6015 = part # or sequential serial, I'm not sure. I believe this is the key to determining whether it's a 400 or 351M without taking things apart.

A2G= the actual date of manufacture. I need to take another look at my number and make sure the G isn't really a C.

And of course, Bill is right on with the "full size car" category because I'm being told that just because it was intended for a Galaxie doesn't mean it ever made it into one. Was probably not originally in a truck, though.

Anyways, thought I'd post my findings.
Thanks again for the help.

 

>Ok, I did a little more research on casting codes. Not
>finished yet, but what I have so far....
>
>D1AE 6015 A2G
>Correct me if I'm wrong, but it breaks down as:
>D1 = 71 (Casting Year or design year)
>A = Galaxie Car line(O=Fairlane/Torino, S=Thunderbird,
>T=Truck, etc.
>E = Engine

Info I have says A stands for Full Size Car but Galaxie certainly qualifies.

>6015 = part # or sequential serial, I'm not sure. I believe
>this is the key to determining whether it's a 400 or 351M
>without taking things apart.

6015 is the basic part #. My info says that 6010 is the basic part # for blocks but it may be outdated or just a typo. Either way since they share blocks I don't think that it would say for certain whether or not it's a 351M or 400.

>A2G= the actual date of manufacture. I need to take another
>look at my number and make sure the G isn't really a C.

I believe that's a revision code not a date code. The block casting date is cast below the casting code. There is also a build date code which is stamped, not cast, into the front of the engine on the lower right (pass.) side next to the timing cover.

 

That explains why the last part, A2G, didn't make sense to me as a date code. I'll look for that stamped number, too.

The reference I found used the 6010 when referring to blocks, too. That's why I was hoping for the 6015 to identify it further. According to an old tech at my local dealership, it doesn't. Basic part # is all it is.

Oh well, the basics have been answered...full size early 70's car engine in a 79 truck. Interestingly enough, my last truck (72 F250) had a 390 donated from a 64 (I believe) Galaxie. At least that one I knew the history of.

 

Ferrite,

Just to clear up a couple of details:

6015 is the casting ID code for an engine block. 6010 is the basic part number for an engine block part. Technically, the 6015 really identifies the raw casting, where 6010 identifies the finished, machined (i.e., ready-to-use) engine block component.

As Bill mentioned, since the 351M and 400 used the same block, the block casting number is inconclusive. However, in 1971-73 model years when D1AE blocks were used, there was no 351M. Unfortunately, there is no way to tell externally if it was rebuilt as a 351M after its original manufacture.

Block casting date locations vary, depending on where the block was cast. Date codes on blocks cast at the Cleveland Foundry (CF mark) are located just below the block casting ID code, below the right cylinder bank. Date codes on blocks cast at the Michigan Casting Center (MCC mark) are located on the top rear of the block, beside the oil pressure sending unit hole.

The original build date code is stamped into the machined front cover seal surface, and it is not visible without removing the front cover.

As for the origin of your engine, it was first installed in a 1971-1973 full-size Ford or Mercury car, as you surmised. It was certainly not originally in a truck, as trucks were not equipped with the M-block engines until the 1977 model year. Almost all original truck M-blocks have the block casting number D7TE.

 

Thanks, Bubba.

I forgot about the dates of M blocks.
Hmmmm, maybe it's a 400.

You guys are awesome! Thanks for the help.

-Ed

 

Not to be one to add fuel to this fire. but my 400 has a casting of DIF.

 

[updated:LAST EDITED ON 16-Dec-01 AT 11:11 AM (EST)]>Not to be one to add fuel to this fire. but my 400 has a
>casting of DIF.

Doesn't sound like you're looking at the right casting code but then again I've seen some strange stuff. I have 2 cranks in my garage right now, 1 351M and 1 400 with no casting codes on them at all.

 

I have a part number of D1AE A1C - the block
where the casting plant should be is DIF - i have been told this is dearborn iron foundry
casting date is 2C21 - 1972/1982 march 21 - believe its 1972
above the DIF I also have a E2
then on top of the block is a number stamped 2N129618
where the build date is found its stamped O or 0 18P