Q&A: Have 77 ford -351m nice clean truck, looking to restore and would like to know about fuel injection options?
September 20th, 2010 | 
Author: Question by JALISCO: Have 77 ford -351m nice clean truck, looking to restore and would like to know about fuel injection options?
as well as companys that offer upgrade parts for this type of engine,these old ford trucks are all steel and tuff as nails no plastic junk ,but they love gas, so far i have looked at a offenhouser intake that claims to improve fuel economy, i was thinking maybe to mix a newer aluminum intake with a factory fuel rail injection system and wire in the computor and other parts from a later model truck motor, i realize i would have to boar the holes for the injectors and build the air inlet control parts from other units, but all in all can this be done and what other problems could i run in to, also the fire to the plugs ? maybe a mag type distributor or what, iv’e had this truck since back when i was in school and really want the mpg to improve as well as dependable for long trips, later i want to give to my son when everything is problem free, if anyone out their can give me solid info it would really make my day, thanks so much for your help.
Best answer:
Answer by rakel-de-freitas@rogers.com
Your best bet is to obtain a “donor” vehicle. Get a wrecked 2000 and up F-series truck with let’s say a 5.4L SOHC V8 with a 4R100 transmission. That would be an EXCELLENT combination. The horsepower & torque of that drivetrain would easily surpass your 351M. Just make sure you get EVERYTHING, and wire it in accordingly. You could even fabricate your suspension to accept the 4-wheel disc brake set-up depending how handy and creative you are. Hope this helps.
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If you can, which you can’t with that engine it’ll cost a hell of a lot of money.
You can always change the rear axle ratio, for better fuel economy.
The biggest problem is the motor. The 351m is junk. It’s mains are too small and the cyl. wall are too thin. They’ve been pretty much abandoned by performance manufacturers making getting high quality parts for them difficult. You can get throttle body injection systems, but I really wouldn’t waist the money. A good Edelbrock carb will work fine. The best upgrade I’ve found is to put a MSD system, all you need is a 6A box and coil because the distributor will fire it (it’s the same type that MSD uses). I would recommend going to a 351 Windsor, if you want to keep the modified find a good rebuilder if you don’t want to do it yourself. With a solid rebuild on the motor, tranny, and suspension you should be able to go a long way.
If you really want to run injection,look into Holley for an aftermarket set up.I love those trucks,but don’t think much of the 351m or 400m.A 460 will bolt right in.
You probably have a C6 transmission, they are almost bullet proof, but use a lot of engine power to operate the internals. If you don’t mind shifting a manual trans, a late model 5 speed would get you at least 2 -3 more mpg. Another easy swap would be to drop in some taller gears, 3.0 to 1 is about right for an automatic and 2.75 to 1 for a manual.
I had a 2 wd 79 with a 351m and C6, the best mileage I got was 14 on the highway. If it were mine, I would consider swapping in a later model fuel injected 302 with an aod trans. Everything you need in the wiring & fuel department should be available aftermarket.
I fully agree with the first answer. I love building older vehicles, but with updated mechanicals. 5.4 with overdrive automatic transmission would make this great old iron giant a modern day
marvel. Plus they have much more room for new engines and upgrades.
First of all, we need to fully understand the 351M engine. The M stood for “modified”. And that’s what it was: a modified 400 engine to displace 351 cubic inches. Basically, it was a destroked 400. With that said, the only intake manifolds that would fit the engine would be the 351M and the 400 manifolds. And since these engines were never considered for race applications, they do not have a wide range of aftermarket parts available. And fuel injection is one of those parts that were not available. 1982 was the last year that the 400 was available in the truck, and ’80 thru ’82 you had to have a ton truck before it was available. The transmission bolt pattern for the 351M/400 is the same as the 429/460. So if you change to any other engine and want to use the same transmission, your only other options are the 400, 429, and 460.
Now, lets suppose you want to go to a small block (windsor style) and want to have fuel injection. The ’88 and later 351W engines were equipped with fuel injection. It would be a sweet truck. As one said, the 351M was junk. However, the 400 was a work horse. I know by personal experience with both. The 351W was a stroked version of the 302, and has a taller deck than the 302. The problem you get into putting the later engine in the older body style truck is the sump location on the oil pan. The older Fords had a front sump since the steering linkage was located behind the front axle. In 1980, they changed the truck and moved the linkage forward, thus moving the sump backwards. So if you use the later 351W in the older truck without changing the oil pan, pickup tube, and oil pickup, the pan will rub the steering linkage. Bottom line is that in order to be able to use a 351W in an older truck, you have to have a 351W oil pan from a VAN. The truck (up to ’79) never had a 351W, and the 351W car pan has the drain plug in an awkward position. You can use the car pan but it is better to get the van pan. My dad and I had a salvage yard for a number of years and built a few of these trucks that body style for “toys”. Our last one was a late ’77 that was titled as a ’78. Looked like a ’77 but when Ford sold it, they put a ’78 VIN on it from the factory. Anyway, it was a 3/4 ton flat bed. We used a 351W from a 1984 Ford van. Also used the transmission as well. Had to modify the shift linkage just a bit, but no biggie. In other words, we just used the complete engine and transmission without any major modifications. The van pan cleared the frame quite well. We also put a 3.73 posi rearend under it and with the two combined, we got 12+ mpg. So if you get a 3.50 gear ratio, with the 351W that should in and of itself improve the mileage. You would still have some good pulling power and be streetable enough to take on the highway. Plus with the 351W, you can get all sorts of aftermarket goodies to build it any way you want to!
Is your son old enough to help? If so, make it a father and son project! Good luck.
The misinformation concerning the 351M is amazing. Just to take issue with a couple of the assertations above: The main journal size is considered too large, although it’s the same as the 351W, to be a performance engine. Also the 351M is a tall deck Cleveland, not a destroked 400. As to performance parts, any 351C intake will fit with the use of spacer plates. Heads are interchangable with the 351C as well as all valvetrain parts with the exception of pushrods. Since the crank main journal size is the same as the Windsor, Eagle stroker cranks can be made to fit, and 351C pistons can be used on the 400, but not the 351M, if the rod small end is bushed.
Now as to your question. There are a number of resources you need to check out to do this. http://www.ford-trucks.com is a good source of general info. There is also a dyi efi mailing list/group whose true name I have forgotten. The network 54 Cleveland forum is also good. Alot of the Pantera guys have converted 351C engines to EFI so you may want to search on that.
As far as I know there are no bolt on EFI kits for this engine. The generally accepted route is to have injector bungs welded onto a good single plane manifold. The Parker Funnelweb, if you can find one, is a good candidate. A throttle body with a carb style mounting flange and fuel rails and the required sensors takes care of the engine mods. Modify the fuel system with a return and a high pressure pump, add a oxygen sensor to the exhaust.
At this point you have to decide what kind of controller you want. Holley or Simple Digital Systems and even some home soldered system that I can’t remember are all options. This won’t be cheap, but it can probably be done for ~ $2500.00, maybe less if you go the junkyard EFI route.
If you don’t enjoy the research and fabrication necessary for this kind of mod an engine swap may be what you want. A 429/460 won’t just bolt in, but there are swap kits available. Also check out fordcummings.com for diesel swap kits for this model truck. Thats probably the best bet for a real milage increase.
As to the distributor, a 460 EFI dist will drop right in for this swap.
No offense meant to anyone about the performance capabilities of the 351M. It’s no dragrace motor or 350 chebby. But there *are* parts out there.
Find a 400m at a salvage yard and rebuild it . Roller rockers , a decent cam and headers will be all you need for a truck. I would recomend a holley 670 avenger carb and an edelbrock intake . If your determined to build injectors go for it , but it think you would be happy with the holley , these components will never leave you stranded on the side of the road . I have an aftermarket distributer that is a ford base with the gm HEI brain and coil built into the cap , Its a neat one wire hook up , and the guts a easy to replace ( stock GM ) if it ever breaks on a trip somewhere.
A injection system for a 351 is not possible to find.Your best bet would be to get a late model truck,and replace the whole power plant.
Holley makes a universal Throttle Body Injection kit that will bolt onto any stock 2BBL manifold. They work great for the street and the cost has come down in the last couple of years.
Forget it,maybe do the eng.swap if your competent,otherwise leave it alone ,or put a small 4 barrel carb,and drive light footed