DeTowman Wrote:Moved the oil returns & made them larger...but they didn't move them much, but enough that u couldn't interchange anything. I always thought it was the 351/400 modified myself..
Yes there is a 400M it says whether it is a 351 or 400 on the original valve cover. The rods and the crank are different giving larger displacement for the 400 with shorter rods and longer stroke crank.
The heads are just like the Cleveland (Small Block). The bottom and bell housing (same pattern) is the same as the big block (460).
Yeah, Ford never "called" it a big block but it is the biggest engine in the 73 to 79 4x4 trucks, 460 never put in the 4wd, that is why you see the custom motor mounts for the 460s.
Now if you want to stick with the naming convention Ford used for engines, the M is for Milton, where the engine was manufactured. Just like Cleveland, and Windsor for where those engines were made, but Ford never said so.
I am a M engine fan, lots of torque, lots of parts, new valves because the factory ones get burnt, high volume oil pump to stop the low end knock, and a good cam to get the valve to open correctly and you have fixed the choked down engine that Ford had to make at the time, 1979 351M had 120hp from the factory to make the government happy, easily fixed. If you find a 1971 351M it had 11:1 compression and runs great!
:rebel: