351/400M Big Block Or Small block

[DeTowman]

all of my resources have said that the 335 series was based off both small block and big block engines.
and its 351m / 400 there is no 400m .

edit: i read the post you called me about. those guys get bent out of shape quick over this subject .

Yes they do & it's just an opinion.. as I remember from Ford tech school the reason for the M series was the Cleveland had an oiling problem after about 50,000 miles if the owner did not change the oil regularly or changed different brands all the time the oil returns in the heads would sludge shut...Thus holding the oil in the topend....Ford knew of this problem & redesign it and they changed the name to the Modofied series....