I have a `79 F-150 Ranger Custom XLT 4x4 Supercab with a 351M, which is only running on 7 cylinders now, after approx. 350k miles. I am going to be getting a new motor for it, but am debating between a 351M & 400. I know through KBB and NADA, the truck with keeping a 351M in it, yields between $250 & $500 more than with the 400. Anyone know why!?

Also, does anyone know what the specs were between the two motors when they hit the streets!? Wasn't the 351M somewhere around 160hp and like 200ft!?

I understand that the Midlands are esentially the exact same block as the 400V, in fact, the parts that I have bought for it are listed as a 400, instead of a 351. So what is the big difference!? Just the crank and the rod size!?

Any help would be appreciated. Not looking to hot rod the truck, since it's a 4x4, I don't want to build the motor to where I have to have a 3k stall in it, then what is the use of having the 4x4?

Basically, looking for streetability, durability, and fuel mileage.

 

Go with the 400 but do these things to it.

http://www.off-road.com/ford/flashback/400_power.html

http://home.earthlink.net/~bubbaf250/index.html

 

go with the 400. don't worry about KBB and NADA, with these trucks that hardly means anything anymore. prices are based on what you want to pay, the condition of the truck, and the avaliblity of the truck.

Oh yea and the 400 will almost always out sell a 351m. same engine, 400 make more power.

 

Well, looking at the 400, it is not even 10 hp and not even 15 ft lbs.

As far as it goes for doing all the hi po stuff to the motor, that's just plain stupid if you ask me, for doing it to a daily driver and part time four wheeler.

 

The difference is crank and pistions. The 400 has more stroke than the 351m so your torque is going to be better. I've got both and even though it can be peppy I'll never got back to a 351m.

 

mine is daily driven, those things make a world of difference in waking these engines up, and doesn't hurt drivablilty. fuel econ. stays about the same no matter what, so why not get more power with it? all in all it's up to you, but i think you need to look more in to it if you are going to rebuild it because there are alot of things you can do to improve these engines. i just had mine rebuilt and love it.

 

Ive got the 400 in mine. I have no complaints with the power. It'll jerk the truck off the ground if I let it! Has a bad miss at mid throttle, like its cutting out when I open her up. Not concerned right now because I drive it two miles to work and back every once in a while. I think the 400 suits this truck well.

 

You can find out more about the 351M and 400 with a search and some reading in the Cleveland forum here.

 

the real difference between the two engines is that my 351M gets 16 MPG, and my brother's 400 get 12. They are both completely stock, with the exception of a electric fuel pump on the 400.

 

Go with the 400. My dad just rebuilt his 400 and installed flat top pistons used in the industrial engines. Other than that he really didn't change it much. It pulls real hard and I was very impressed with the power it had.

 

Yeah... That's what I was thinking... Since they are both basically the same block, and I can get either from our source at work, I was just trying to figure out which way I wanted to go.

I was thinking that... 400 with a 4 barrel 650, since a 400 uses MAYBE 680 cfm at its peak, the C-6 has recently been rebuilt, and the 9" has a 4:10 locker in it, so I figure the gas mileage with that motor, rear end, and the 35x12.50's, I should be around 15 or so.

 

15 is a little optimistic. i get 10 with 3.55 rear end and 33" tires

 

Get a 460, same bellhousing.

 

I was actually thinking about the 460, but remember.. Out here in California, we have that damn 4 letter word... SMOG! The tag on my truck shows I can get away with a 5.8/6.6L. I was thinking about a 460 before, but there's always that chance with smog!

Plus, what were the specs differences stock between the 351/400 & the 460!?

 

usually if you have all the required SMOG equipment for the year of the truck, you're OK, but that can vary from county to county.you could ask some local shops that do this kind of stuff about the legality of running a 460.
I think the 400 made slightly more HP than the 460, but less torque, I could be wrong.
in a forum like this, most will advise you to use the biggest engine possible, whether you need it or not.
of course I got a 460, so I can't talk