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. Posted using the Full Custom H.A.M.B. App!