i recently purchased a 1079 ford f150 with a 351m in it some of the people i have talked to say its the worst engine ford ever made and if so what engine do u preffer?




i know u guys will help me with this issue thanks.

 

I prefer the Ford 400 ebgine !

 

Personally, the 351M/400 block is not a bad daily driver. I've had three (in different vehicles) and they served very well. All of them have dealt with heavy foot and high demand; none quit running. Modifications, as to higher output, are a big problem. It is hard to get better horsepower out of the motor designed for better fuel economy, so to speak. My husband hates this motor and calls it the "boat-anchor"! Basically though, the lack of availability for increased horsepower, is his main complaint (along with it being very heavy, cast iron does that...).

 

I sure don't think its the worst. But thats all just a matter of personal opinion.

Myself, I thought the 352, and 360 was the biggest piece of crap ever. There again, thats just my opinion. I never had one that did not burn a fair amount of oil, and yes I had brand new ones too.

 

Not likely. There were no Ford engines made in 1079.

 

NO NO NO NO The 305 is the most productive boat anchor ever made, and the worst motor...


Oh wait thats a chevy motor

 

Technically, Scroob is right.

However, a 351M isn't all that bad. With a few simple mods, it can actually be a powerful and reliable motor. Swap in a new cam and timing set and it will make a world of difference. You are looking at $200 or so to do this. Add an aftermarket aluminum intake and a small 4 barrel carb and you liven it up even more. But what these engines will really respond to is more compression. If you want to rebuild it, you can get gobs of power out of it by putting in new pistons, the cam, and the intake. Add a set of headers to that and have a serious powerhouse under the hood.

Look around in this forum and read some of the threads about cams and engine rebuilds. These guys in here have really put a ton of good information in this forum.

Also, if you rebuild it, put a 400 crank in it. Theres no substitute for cubic inches when it comes to making power.

 

"Basically though, the lack of availability for increased horsepower, is his main complaint (along with it being very heavy, cast iron does that...)."

Actually, the 351M/400 is one of the easiest to get increased horsepower from. He's probably thinking about intake manifolds. That's not a problem either, as the 351C manifold bolts on with a couple of spacers.

A cam, 4V manifold/carb, head porting, and headers can put you over 300 HP. I can't think of any other engine you can get more out of with less effort. This can be done without even pulling the engine.

As far as weight, they only weigh 50 pounds more than a 351W, and 150 pounds less than a 429/460.

 

Scroob, my husband has two words for you: Volumetric efficiency.

You are right on the weight issue also, he clarified that shortly after I wrote the previous thread. One other point to also add to my statement, "Modifications, as to higher output, are a big problem. It is hard to get better horsepower out of the motor designed for better fuel economy, so to speak.", is that aftermarket products for these motors are quite expensive due to lack of demand. Why build an expensive 351M, when you can do much more for the same amount with a 302?

 

PS - The article to read about the build up of these motors is:
"High Performance Options for the 351M/400 Engine"
by David Resch
It is archived on this site, https://www.ford-trucks.com/articles/mblock.php
Smile and make it a good day!

 

Building a 351M/400 is not that expensive. The Hot Rod build that got 385 HP and close to 500 ft/lbs. of torque from a 400 spent less than $2000. That was a complete engine rebuild, using the stock carb and manifold for smog reasons. If they'd gone with a 4V manifold and carb, way over 400 HP and 500 ft/lbs.

Why use a 351M/400 over a 302? To be blunt: *****. You could spend 3 grand on a 302 and not come anywhere near the torque a mildly modified 400 will put out.

A Comp 255DEH cam, a 4V manifold and carb, and headers, and you are already in the 350 HP and 450 ft/lbs. of torque range, with no other mods. You're talking serious bucks to get a 302 into this range, and you're really just beginning the process with the 335 motor.

Your husband seems to have the wrong take on these engines. They were designed to replace the FE series, specifically the 390. Ford already had plans on the board for high output 400s, when the smog and gas crisis hit and reduced them to choked down smog dogs. They were never meant to be gas mileage engines, even though they were designed to deliver good economy while making excellent power. Take a look at the heads. They were meant to be free breathing, light weight, large displacement engines that would give the Chevy 350/400 a run for it's money. Due to circumstances, that never happened. The potential is still there, and many have learned to exploit it.

Incidentally, there never would have been a 351M if not for smog. It would have been the 351C (high revving Chevy killer) and the 400 (stump pulling torque to move large bodies.)

 

have alot of 400 cranks laying around do ya?....

 

400 cranks are very easy to find and inexpesive as well. You should be able to pick up a good machined 400 crank for about C-note.

 

From what I have researched the 351M and 400 actually have one of the highest potentials to gain power, mainly due to the fact that they were so choked down in the 70's, and the motors never really had a 'high performance' factory version ever. It is a very common belie (misconception) that these were the worst ford motors. That article linked above is a great article for anyone that has doubts about the M-blocks, very informative. And you got to remember the times... like when they compare it the the 460 in that article. The 460 has long been a favorite among ford enthusiasts... but you'd be surprised how close the 400 was to the 460. Yes there are factory flaws in the motor, most of wich can be easily corrected. Do a little research here and on the web and anyone can see the potential.

The main disadvantage of the motors is that do to common misconceptions (and that they were only in production for about 10 years)they arent very popular, and therefore there isnt as much aftermarket support for them. But there popularity is growing fast and there are more and more parts comming available for them.

 

everybody is saying to increase the compression but according to the attached post form above the only manufacturer of pistons is trw and 8.6:1 is not a very high compression ratio.