To make a long story short, will a '74 351M bolt into where my '79 351W was? I've heard that it will...and I've heard that it won't. I'd like to know the real answer before I drive myself crazy trying to find it. I'm running an NP435 if that matters. Thanks
The M is a modified 351C block with a 460 deck height and the bb bellhousing pattern, it's taller, wider and heaver than the W, not to mention it was built during the smog era, and, is a HUGE dog stock. If you are thinking of using one, re-build it with a 400 crank and pistons, 4" bore, 4" stroke = torque monster.
You would get the bellhousing from a truck that has the 351M to an NP435. Probably find it in a late 70's ford pickup. I actually have on sitting in the garage if you want it email me. It came out of a 79 f150 with a 460 I believe.
I was doing some searching in my Ford books that I have. I found that the 351M didn't come out until 1975. The number on my block says D4AExxxxxxxxxx making it a '74. I'm going insane....................
The casting number has nothing to do with what year the motor is really. The casting number just tells you when that casting was first used. Since the 400 shares the same block having a '74 casting number doesn't necessarily mean the motor is a '74. I'd be willing ot bet the '81 351Ms used the same '74 casting.
But the big question is WHY, WHY, WHY, WHY?????? would you put a 351M into anything? They suck unless you turn them into a 400, and even a 400 isn't anything to write home about in stock form. Just get another 351W and be happy with it...
Guys, thanks for the help. What I'm leaning towards right now is getting an AMC 304 and a "special" pilot bushing from AA. The bellhousing pattern is the same. But who the hell knows, I will probably change my mind tomorrow again.
If I do keep the "M", there's no way in hell it's staying stock. I didn't rip it apart for nothing. I plan on an Edelbrock Perf. intake, either an Edelbrock or Comp Cams 4x4 cam, a Rochester Q-jet from BC Broncos, and some other little things. Also the 400 crank if I can find one.
I need to know how to tell the difference between a 351C and 351M. I know that the M is a modified Cleveland, but how do I tell what I have? I want to sell it, but the price will be pretty different if it's a Cleveland compared to an M.
Also, I decided to keep my 351W and pull it, build/rebuild it, and put it back in.
This is the bellhousing pattern you will find on a 351M, 400, 429, or 460: BBF pattern
This is the bellhousing pattern you will find on a 289, 302, 351W, or 351C: SBF pattern
Just to fawk things up, Ford made a 400 in '74 with the small pattern that went into some passenger cars. Like others have already said, the 351M/400 are taller than the 351C, and also have a wider intake manifold.
A forum community dedicated to custom off-road vehicle owners and enthusiasts. Come join the discussion about trail reports, builds, performance, modifications, classifieds, troubleshooting, fabrication, drivetrain, and more!