I am looking to purchase a classic Ford truck. I am looking for a F100, F150 or ranger in the 1975- 1988 range with focus on locating a 1975-1979. I have located one that I like. The owner is extremely proud of what he is calling a 400m big block. So let me state I know very little about the guts of a truck. I have been researching the 400m and have not located much positive information about this motor. I thought I would post this message to get "professional" help. I welcome all feedback and advise on the year and model of classic ford that I should target. I know the visual things that I want (i.e. single cab, short wheel base, no rust, clean title, bench seat, etc.). I will be using the truck as a second car. It needs to be dependable and I would like it to retain value and not be replacing the engine or spending a lot of money on repairs. If the 400m really sucks what should I be looking for?
Thank you in advance for your time.

Dec 9 up date. Truck was described differntly than what I saw. Truck was advertised as rust free. Thanks to Mike I knew to look at the inside of the cab bed - rust on floor pan with a metal plate bloted down. Next major issue was the inside cab and door jams were "original" ford light green. The outsde was painted Ford Forrest Green that was peeling/flaking on every section; like when you paint water base paint over oil base paint - that would be a expensive mess to clean up. Banged up driver quarter panel and there was something on the truck that made it is so loud he had to turn it off so I could talk (My 87 year only mother and her 16 year dog will be riding in my tuck - simply will not work) So the clean up on the bad paint, the rust and the not so honest owner will keep me looking. Y'all will hear from me again.

 

You're going to get a lot of different opinions on the 400. First of all, a 400 is NOT a big block. Secondly, a 400 is just a 400. The 351 has the "M". Ford took their 351 Cleveland and changed some things on it. The biggest change was they stroked it to 400 cubic inches. They quickly realized it wasn't a good idea to have that long of a stroke, so they "modified" the 400 by de-stroking it back down to 351 cubic inches. SO. A 400 is a 400 and 351M is a 351M.

Ok, that's clear. Now let me say this. I absolutely HATE 400's. With the white hot intensity of 10,000 imploding supernovas, I hate 400's. Their bottom ends are weak and they are unreliable in my opinion. BUT as I said, you will get lots of opinions on this one. This is just MY opinion.

If you want to drive this truck everyday, I suggest you concentrate on late model '77 to '79 trucks. These later trucks already have the upgraded steering, power disc brakes are common, etc. The "bullnose" trucks, (1980-1996) I wouldn't bother with. I don't like the looks of them compared to the dentsides and the chassis aren't built as well. I hope this helps.

What year is the truck you're looking at and what does he want for it? If that 400 is stock and it's never been touched, just assume you'll have to rebuild it within the first year. I had a few of them and they all had a bottom end rattle after I bought them.

 

Alan
Thanks for responding. The truck is a 1977 F100, standard wheel base with factory A/C. Automatic (I need automatic) He indicates that he is the second owner. All new electrical parts, car air breather gas tank and fuel pump. Was repainted about 2 years ago the original green color. It is a dark green solid color not two toned. Body looks good - clear title. Bench seat with a cover. Interior is ok but I would want have the seat recovered to original condition. Price is $3250

How much does a rebuild cost vs. replacing the motor?

 

I'd just swap in a 300/zf5 out of a 90's truck. Especially cause it is a 2wd longbed.

 

Welcome to FTE.
I bought a new F250 in '77. I don't have any major gripes with the 400 just that it felt underpowered. My particular truck had problems with valve springs breaking (three times) but that was 35 years ago. Other than that it was relaible and never left me stranded.
Personally I'm an FE fan (360/390 engine family) but these were discontinued after the '76 model year. The 400 replaced the 390 in '77.
the 1977 model year is considered by some to be the "pinnacle" for the 73-79 dentsides.
Anything mechanical can still be fixed relatively easy, parts are readily available at any auto parts store.
Body-wise the "biggie" is the floorpans, under the carpet. Take the time to pull the carpet up and look at them from inside the cab. Floorpans go bad from the inside out. They can look near perfect from underneath and be paper thin or have scally rust and pin holes developing not visible from underneath. Another body area to look at are the rear cab corners, the area above the rear wheel wells, the lower door sections are also an area where rust likes to develop.
With the 400, the automatic trans will be a C6. In my opinion the best automatic that Ford built. Strong, reliable and not very expensive to rebuild.
If the truck is in really good shape and mechanically sound, I'd say $3250 isn't too bad.
On engine work, if you're comparing a complete engine rebuild (with machine work) vs. buying a remanufactured long block from like Jasper engines or the like, it's usually cheaper to go with the remanufactured unit.
The only drawback to owning a dentside for the first time is getting used to driving something with a carburetor rather than fuel injection.

 

It sounds like a pretty nice truck. The engine can always be replaced. I'm like Mike. I like the FE engines. I'll be replacing my 300 six with a 390 in the spring time. Be sure to check the areas that Mike mentioned because the man knows his stuff. As far as the engine cost goes, I like to rebuild. A crate engine IS cheaper, but after touring the Jasper plant and seeing main caps and cylinder heads being installed with a 1/2" air impact, I'll just build them myself. (of course this was MANY years ago, they may have gotten better since then)

 

I would stick with the 73-77.4 range. As for the engine, I like my 460 but I would prefer the 390 for gas reasons. I had a 400 in my 78 trans-am and the thing never worked right. Probably more because of the transplant but not a fun experience. You can always swap in a diesel. I don't know what your intentions for the truck are but I would make sure you get 4x4. Just one more thing in your back pocket if you ever need it and not fun to swap in. Good luck!

 

Mike that you for all the detailed information. I will create a checklist to ensure that I do not miss any of the key points that you provided.

 

I run a '78 F250 4wd with the 400. I purchased from my father in law. Its fairly low miles and I also use it as a second car and weekend work truck My younger daughter loves driving it when she is home.

Besides the engine, there are other differences between the years. Some earlier/mid 70's trucks used "power ram" power steering... basically a hydraulic cylinder to help turn the wheels. Service is difficult and expensive with this setup so I'd check that out.

On the engine... the 400 is like any 70's V8 which wasn't the most efficient with low compression emissions technology of the day. That said, the dead stock engine in mine does fine. I haul the occasional heavy load and tow 3000-4000# without strain. The 400 is very much upgradable if desired. Tim Meyer is a specialist in these.

TMeyer, Inc. Precision Automotive Machining

 

Any of the bad 400 were long since junked,Nothing wrong with a 400 if you upgrade the cam and springs....You didnt say 4x4 or not but if your looking to drive it stay away from a 460 unless you have the funds to supply 7mpg =ON A GOOD DAY= My 400 got 8mpg! if your going 2x look for a 302-351w but its one of them things your gonna get what you find 351M-400 with a C6 is in most then sticks then 302-351m then the 6banger nothing really to worry about with these things they are tough trucks.

Just check the frame really good for any accident damage.

The trim will set you back a few $$$$ but everything is available for them in the after market.

 

Blue and White
Thank you for the information. Everything is set for a Sunday viewing and test drive. I have received valuable information from this forum and think I will be able to make a better decision about this truck.

 

Your information is incorrect There is no such thing as a 351modified or 400modified the m stands for Midland which is the plant that it is made in just as the Cleveland was made in the Cleavland plant thats it. Yes they are the same motor with different strokes.

To the OP
The 400 is good truck motor for a truck that is used as a truck it has more torque then the 351 but is no race/ hotrod motor and just like all motors of that era they are very inefficient in their stock form.
So if you are looking to have a hot rod the 400 might not be the right choice for you but if you are going to be towing or hauling stuff it should be just fine.

 

A 400 in stock form leaves a lot to be desired but if built right can be a powerful and dependable engine. Just have a look at the 335 engine forum here at FTE. Good luck.

 

I unlike many on this forum absolutly love the 400 and with a little bit of work suck as a carb and intake swap will have all the power you could ask for. I use mine as a pulling truck and it does fairly well but i will agree the bottom end is a bit weak as im currently replacing mine. Just my opinion good luck with whatever you do decide.

 

All of these options have there postitive and negatives for me it is 460 all the way! To quote from some unknown sage "there is no replacement for displacement"

Really though I would be more concerned about the rest of the truck any of these engines will perform well if treated properly.

Goos luck!!