what i do know is that it is 78 F-250 super cab 2wd long box. 400m w/c-6. Has factory air,cruise ,towing mirrors, heavy duty cooling,trans cooler, p/s cooler.3"rear springs w/5 leafs. heavy duty brakes. question is is it a camper special without the badges. truck seems to be set up for serious towing. i hope so .

 

look in the FAQ forum there is info there or do a search you will find tons of info.
i found this old thread might help you out..
https://www.ford-trucks.com/forums/s...ghlight=towing

 

All looks good except there isn't an M after 400.

The M follows the 351M no 400.

Also, there hasn't been anything definite regarding what the M means.

All M discussions are like trying to a catch a dust mite.

That's why we don't talk about it anymore


Why is your address in your location ?

I wouldn't put that on here, maybe change it.
That space is for the town/city you live in

 

I think the "M" stands for modified....if I remember correctly they used windsor block and cleveland heads...didnt really catch on...so must not have been a world beater...was made in mid 70s....believe there was a 351 and a 400

 

The M is just M and no more as far as anyone can prove. The 351M and 400 are not built up from a Windsor block. The block is the 335 series and the heads are almost identical to 2V 351C heads.

There are more 335 series details, but this isn't the forum for it.

 

Look at the door tag for GVW info, that should have a higher rating than the standard F250 (I think...).

--Mike

 

I was under the impression that 351M was a 351C with 400 heads......

 

put "ford 351M" into dogpile search engine...theres a bronco site that has all the info you want....

 

No, there are two different blocks. One is a 351C only block and the other is a taller deck version for a 351M and 400. The heads do interchange somewhat though.

 

ok hear we go, the m is to help diferinciate (sp) between the 3 motors the windsor, clev, and M, (rumors of it being made in the michigan plant) it became known as a Modified and just kinda stuck. it is a clevland block with a 1" taller deck hight and different main bearings. all 335 series motors ( 351m, 351c, 400) have interchangable heads along with a lot of other parts in the motor. yes i know not the place to put this but i want to put some stuff to rest