ford 400m engine

I know this is an old thread, the 351M controversy seems to go on forever. I worked at Ford dealers for well over 20 years and done everything from new car get ready to service manager and all line positions in between. I was therewhen Ford introducedthe 351M IN 1975. If I looked long and hard enough, I could find my new product book for 1975 that introduced that engine. It was introduced to meet the strickter emissions standards out that year. It was given the 351M designation to identify it as a MODIFIED, short stroke 400. They did so to diferentiate it from previous 351/352 engines i.e. 351C (Cleveland), 351W (Windsor), and 352 (FE). It uses the same block, heads, internals, and 385 series bellhousing bolt pattern as the 400 that it was taken from. The crankshaft is unique to it because of the 400 size main journals. In stock form, it is avery dependable, long lasting slug. The easiest and cheapest favor one can do for this engine is to install early tming gears that run the cam timing straight up. Al the other usual hop up tricks apply once the cam timing problem is cured. The block cracking problem occurred in 1978 &1979 and was covered under the A40 recall program. The cracks would occur in the lifter valley just above and at right angles to the lifter bores. We made lots of money on that campaign and Ford took it inthe shorts PR wise at that time. I hope I have cleared up any confusion about the "M". I have no idea where the "Midland"fairy tale came from, but it sure wasn't Ford.

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I was always told that there's no replacement for displacement.... So wouldn't the 4" stroke paired with Cleveland performance parts make it a worthwhile engine? The stock cam specs even with a stock rocker ratio of 1.7 are sad but the engine makes torque down low like trucks and hauling vehicles need.

 

I was hired full time for 18 months by a local Ford dealership when they needed extra help to cover the recall on those blocks. That's why they called me engine man. It was a pain taking those out as the AC housing was in the way. Ford also had a problem with the number 3 piston knocking. I never really understood why it was always number 3 but the skirt diameter was always smaller than the head of the piston. If the pistons weren't measured when the blocks were replaced, a knock would start up shortly after the work was done. I replaced several pistons in those after my time at the dealership.

There was a guy who hauled cattle that bought a truck with a 400 when he couldn't get a 460 in a new one. He ended up buying his old truck with the 460 back because he couldn't pull the weight with the 400 and it used more fuel.

 

Ok motors. Don't like to rev, so keep it under 6K and they will be happy. Really need oiling system help if you are going to run them hard as the mains are huge. Are complete dogs stock, with poor oil pressure, but will run forever with next to no oil pressure at idle, and maxing out at 20psi when stock. A cam/timing chain change, and four barrel intake and carb really wake them up, but replace the oil pump with a high volume/high pressure if you want it to live after modifying it!

The lifter valley cracking was from on 77' and earlier Michigan casting center blocks. They have a MCC identifier cast into them. They best blocks are 78-82 and later as they have additional reinforcing. Heads are actually different than true cleveland heads but are functionally interchangable. All are open chamber 2v heads, but the exhaust port and chamber are not as good as true cleveland heads. M heads will have no identifier on the outside corner of the head, while a Cleveland will have a 2 or 4 cast there to identify 2brl or 4brl heads. M engines only every came with a 2brl carb from the factory.

They all take the big block transmissions, except for one year only (73 I hear) and very rare small block bolt pattern flange block. I have read about them and seen pictures but never seen one in person.

 

heres a pic of the small bell pattern 400. I believe it was early production '71

 

Built one using .030 over KB coated 351C hypereutectic pistons, bushed the rods for free floating pins, Edelbrock performer cam, Edelbrock non-EGR performer 4V intake, 2V heads, roller rocker conversion, double roller timing chain. She runs good. Loves fuel as well as a barnyard dog likes lapping water.

Keep the rod bearing clearances within spec and they'll make decent oil pressure.

Biggest issue with them is finding decent motor mounts for a F150 or Bronco. All made in Asia and require modification to clear the oil pan.