Hi guys!

Just digging around the net and found an aricle on the history of the 351M/400 that you guys may be interested in.

http://www.projectbronco.com/History/history_of_the_ford_351m.htm

Thanks!

Steve

 

Thanks, I found that interesting, since I have an '81 F250. The owner's manual lists 351/400M's for F250/F350 and the Windsor for the F150.

When the 5.8 litre engine is being referred to, I wonder which one is meant. The 'M' or the 'W'?

 

[font size="1" color="#FF0000"]LAST EDITED ON 03-Nov-00 AT 10:39 PM (EST)[/font][p]horsepuller,

Yeah, there are a few inaccuracies in that article about the end of the M-block's production life.

According to USEPA fuel economy guides from 1978-present, M-blocks were used in cars through MY1979, both 351M and 400.

Starting in MY1980, the 351M was available only in F150-up trucks, vans, and Broncos. The 400 was available only in F250-up trucks and vans, except the non-HD 4x2 F250.

In MY1981, Ford replaced the 351M in California-certified Broncos, F150s, and non-HD F250s with the 351W. Both the 351M and 400 were discontinued in all vans in MY1981. The 351M continued to be avaliable in non-CA F150-up trucks, and Broncos. The 400 was discontinued in non-HD 4x4 F250s, but was still available in HD F250-up trucks.

In MY1982, Ford replaced the 351M in all 49-state Broncos, F150, and non-HD F250 trucks with the 351W. The 351M and 400 were available only in the HD F250-up trucks.

MY1982 was the last of the 351M/400 production.

When using metric designations, Ford usually appended the M or W suffix to identify the engine, if both were available (i.e., 5.8M or 5.8W). After 351M production ended, the 351W was the only 5.8 left. Sometimes, production line exigencies render the owner's manual less than completely truthful.

BubbaF250

1980 F250 4x4 Custom, 351M/NP435/NP208/D44HD-TTB/D60-FF/3.55s 6750 GVW, Rust & White.

 

Would you know if I could find out if my F250 has the 351 or the 400 by refering to the code in the doorsill or the VIN? I have always assumed it was a 351 because that's what they said when I bought it used, but I know it has had several owners. Would like to try to find out for certain without having to look at the stampings on the crank!

 

horsepuller,

The VIN has a character that identifies the original engine Ford installed in the truck. I don't know offhand which character it is in the 17-digit VIN.

Regardless, unless you've owned the truck since it was new and you know the engine was never changed, the only way to know what's in there now is to look at the crankshaft casting marks.

BubbaF250

1980 F250 4x4 Custom, 351M/NP435/NP208/D44HD-TTB/D60-FF/3.55s 6750 GVW, Rust & White.

 

Isn't the stroke different on the 351 and 400?? You should be able to pull a spark plug and use a dowel to measure the stroke.

1978 F150 SC 351 C6 $1000
Soon to be Bronc owner!!
1969 Buick LeSabre 400
1941 Farmall "A"

 

>Would you know if I could
>find out if my F250
>has the 351 or the
>400 by refering to the
>code in the doorsill or
>the VIN? I have always
>assumed it was a 351
>because that's what they said
>when I bought it used,
>but I know it has
>had several owners. Would like
>to try to find out
>for certain without having to
>look at the stampings on
>the crank!


Go to http://www.medicine.wisc.edu/~mrm/bronco/ and type your VIN into the VIN decoder he has on the site. It will tell you what engine your F250 has providing it hasn't been swapped.

 

In the VIN number the 4th digit is for the motor. If it is the letter H then your truck came with the 351.... If it is the letter S then your truck came with the 400. These are for the F100-F350 per my Ford book.... Hope this helps.


BJ 77 F150 4x4 400/C6
Flairside "Bubba Grape"