I know most of you say the 351m is not that great of a engine. My 1979 F-100 came stock with it and a c6. I know it will need to be rebuilt one day as it has 100 grand + on the odometer. I found a 351W in the area plus trans. for $300 bucks. It has been sitting for several years but it will be rebuilt anyway. Has 4 brl and high rise intake. My truck is 2wd and I dont ever plan on trying to pull a house with it. I do know that the 351m parts are more expensive then 351w or 351c. Got any ideas? And is there any swap issues?

 

Easier, cheaper to fiddle with the 351w. The 351m has only stock, low compression, down the hole pistons available, so if you want any real beans, you have to go 400.

What trans with the 351w?

You may have to change mounts, not sure of all the details here, but the usual cooling, exhaust, linkages, but it shouldn't be anything drastic.

 

ahh the time honored ?? the windsor or the modified.... i've built both. an the thing i've found with the modern engine builder, its cheaper to buy horsepower than it is to build it. the cost of performance crate engines has come down considerably. to put the windsor in the truck you gotta make sure you have the correct oil pan, and engine mounts. any from the small block will work, and be a bolt in. as far as linkages go, they all the same, depending on your trans. it is possible to get a c6 for the windsor, look at vans through the late 80's. then all the linkage an mounts for the trans are the same. have fun with the truck. best advise i can give you.

 

I went the 351W route. I just wanted a comfortable driver with good fuel mileage. I added an overdrive to go along with my 354 gears.



Doug

 

When I got the truck I had the C6 completely rebuilt down to a new flywheel. That was about a year ago. The 351W and tranny, the guy told me it was a 3 spd with overdrive. I believe that would make it a C6 correct or is it a C4?

 

Stock heads on a windsor arent good. A high rise intake on stock heads isnt good. A high rise intake in a truck isnt good. Youll probably be left disappointed.

351c parts are the same price as 351/400 parts. They are mostly the same.

Put the money into your current engine. My opinion of course.

 

i'd normally vote the 351w, but it'll be a project in the sense of swapping out the c6 too...just keep things simple. the 351m rebuilt without all the smog crap on it, bumped to a 400 will MORE than make you happy and will simply bolt up too.

 

My 351M i am having no problems with at this time. Besides all the smog crap. The 351W would be a back up when the other died and would be rebuilt in the mean time. So same idea, keep the 351M? I thought a 351W came with a C6?

 

Keep the 351m and put in a decent cam lined straight up. The cams in these trucks (351m and 400) are retarded 4 degrees for emissions crap back in the 70's.

A 351w will not bolt up to your existing trans. The bellhousing mountings are different between the engines.
Your 351m should have a C6 behind it.

Making a 351m into a 400 is very easy.

 

So I dont know if I mentioned it or not but this is my daily driver. What does it take to get to a 400? I get 14 mpg now and I am ok with that how bad will it be at a 400? Are we talking a 30, 60, over bore, different heads, different crank?

 

351m to 400 = 400 crank, different pistons.

The auto behind the 351w--"3 speed with OD--that would be a 4 speed OD, possibly an AOD or one of the others--do you know what year the engine/trans is?

Check out the 335 forums, thread after thread on the 351m to 400 process.

If your 351m is running good, run it. You can make a minor improvement with the older or performance timing set to move the cam up to straight up.

 

you are correct, the 351w's came with the smallblock c6's...you could yank an entire drivetrain from a late bronco and swap it in. the 302/351 bronco's/trucks came with the c6 up till 89 or so...actually the 5.0's got the aod somewhere in 85/86ish...so they had the aod with a transfer case that would work behind a 351w, I've known friends to do it. (aod is a 4 speed auto)....and in 90 the 351w got the e4od which was a 4 speed computer controlled auto....junky trans, but good when rebuilt, as they got all the upgrades when rebuilt. Not sure if you could use a later e4od with a carb'd setup or not, but the regular aod is NOT a computer controlled trans. (aode is the computer controlled version)

to make yours a 400, all you need is the crank and pistons from a 400, nothing else. Slam that crank and pistons into your existing block, stick a good cam, intake and exhaust, and you'll double that 150hp that you have now....if not more...I found a used 400 shortblock in craigslist and got it for a whopping $60...lol. It's stuffed with the crank and pistons I need. Hell, the entire shortblock assembly is good, so I will likely rebuild that motor while I drive around the 351m that I have now. Keep your eye on the local craigslist...people yank these 400 engines out daily and practically give them away....don't overlook the little 351m/400...you can get the power out of it that you want, and cheaply too.

I am still considering a 460/351w swap, but I'm highly leaning the 400 route cause the block only cost me $60, and I want to take the time and learn to rebuild it myself.
just be sure if you buy a 400 block, make sure it's a 400, as externally the 351m and 400 blocks look identical....mine was stamped on the side which coded out to a 77 400. You can also tell by id'ing the crank.

 

85e150, what kind of minor improvements? I just replaced coil, control module, and distributor. Everything I heard is that the reman distributor needs to be played with a little as it fits multiple models. It never got hot before and now it stays 1/2 to 3/4 on the temp gauge. The timing is set to 8 degrees BTDC.

 

yea, I just replaced my duraspark too, and I'm set to ten degrees. What I noticed is the vacuum advance is advancing too much much on off the line light throttle..so it's missing just off idle. The vacuum advances should be adjustable with an allen wrench, so I'm going to dial back my advance some

 

Just read through this, including the myths etc:


351M/400 Performance Build Up