i have a 86 bronco with the 351w and three speed auto ( c6 ? ) want to swap in a400m from a 79 truck . what do i have to do to make this work ?

 

why? that 400 is underpowered compared to the 351w. you will need to change trannies also to make the 400 work not to mention change all the frame towers, motor mounts, exhaust etc..

 

ok this is the un dumb question cause im asking it, what is a frame tower and why does it have to be changed? to answer your question the 351 is bad and i have a good 400, bored 20 over and im on a budget

 

Sell or trade the 400 for a 351. Even if you lose a little on the sale you'll still be ahead.

 

You will end up fairly because you would need several modifications as Kem already mentioned to make that setup work.

 

ok thanks for the advice guys, a couple more questions though, are any parts from the M motor interchangable with the W, specifically heads, cam and lifters, and timing gear set?
this is in the interest of my budget, i have these parts new.

 

No, its a totally different engine family. only a 351m & 400 interchange parts. NOTHING from that 400 will work on a 351windsor. the bellhousing bolt patterns are different. as are the motor mounts, frame tower locations etc..

the frame towers/perchas are what the motor mounts sit on and place the engine in the proper location in the engine bay.

 

Guys, you need to chill with bashing the 400. There are far too many misconceptions about this motor, it is one hell of an engine.

I don't totally disagree about it being too much work to swap the 351w for a 400.. I wouldn't begin to have the ability to change frame towers (welding required?). Need a new bellhousing i'd assume.. then issues with exhaust, cooling, etc. and 400 is physically bigger than the 351w, not that you can't fit one in an 86 bronco, but it's not as easy as swapping one into a pre-80s.

HOWEVER, the 400 will totally destroy the 351w in stock performance, especially for a truck/suv. The low HP numbers and an OLD myth (because of the change from gross to net HP when the motor was introduced) make it seem like a dog, but we all know (or SHOULD know) that horsepower doesn't tell the full story of a motor.

Fine, 351w is 220hp (at something like 3500rpms?) and the 400 is something like 200, but that's all at under 2000RPMs.. that's an insane amount of torque.. with the 400, like the 460, you get a steady high torque number across the entire RPM range, with the 351w it just spikes late in the RPM range.. it's a car/race motor, not a truck motor.

TMI just posted a comparison of a stock 460 to a stock 400 in the 400 forums:

https://www.ford-trucks.com/forums/9...60-engine.html

considering these two are so close in performance, how can you say a 400 is underpowered compared to a 351w? it's more comparible to a 460 if anything.

the 400 definitely has its weak points, but I'm sick of this common misconception that it is a trash engine, especially on a Ford enthusiast site.. to the point now people are saying it's actually weaker than a 351? for God's sake?!

 

The worst thing about a 400, is that it's nearly the weight of a 460, with the same motor mounts and bellhousing pattern as a 460, but with small block power. If you're going to swap in 460 mounts and transmission, why not just bolt in a 460? Pound for pound, the 351W is more efficient than the 400.

The airflow of the stock 400 heads will definitely outperform the airflow of the stock 351W/302 heads, since the 400 heads are nearly identical to 351C 2V heads, other than combustion chamber shape and water port locations. However, those same decent flowing heads are known for cracking under load in a truck, I suppose because the 351C 2V heads weren't originally designed for truck service.
Not to mention, the aftermarket is flooded with 351W parts, but the 351M/400 parts are scarce and costly. A built 351W with aftermarket heads would make far more power on far less money than a built 400.

I will say however, that while the 351M/400 is in fact my least favorite of Ford V8s, I'd still take one in a second over any GM motor ever offered, if that means anything. The 400 would certainly run good if you worked it over some, but if I had to choose a gas V8 swap in a Bronco, I'd MUCH rather have a 460 in there than a 400.


p.s. The stock 400 made 160 hp and 400 ft/lbs. Decent torque, yes, but the hp was terrible for such a big motor due to the tiny 2V intake manifold and carb setup, and the similarly gentle camshaft grind. There used to be a 400 4V version available from the aftermarket that bolted up to the 2V heads, and with a 650 Holley on there, you'd certainly have at least 200 hp. But again, you'd be spending a lot more money on the 400 parts.

 

The 400 is a great engine (with the proper mods), i once found a great article on how they made over 360hp / 380lb/ft out of one spending only 2000$ (wich is great considering they almost got 250% gains) and ending with a reliable engine... But the guy is on a budget, so that swap doesn't seem to fit his needs.

 

The 400 weighs something like 50-75lbs more than a 351w and the 460 weighs a good 120-150lbs more than the 400, so I don't see why you think HP to weight performance is so bad?

I can fully understand the 351m. They were being compared to both the 351c and 351w, both higher horsepower, less weight, less smogged from the factory.. but you get 50ci more with the 400 with almost no weight gains over the 351m.

again on horsepower, the 400 made that horsepower at something like 1800-2000RPMs, that's an insane amount of torque for any gasser. the 351w made its 200hp at 3500RPMs, do you honestly care how much torque your truck or SUV has at 3500RPMs? unless you're screaming down a 1/2 mile, you don't even want vehicles like these to hit 3500RPMs in day to day driving, or while they work (offroad up a hill or pulling a big boat).

American Thunder, I'm surprised you're argueing against the 400.. you put a cummins in your Bronco? Seriously, try to discuss HP to weight ratio with a fricken Cummins?

Isn't your engine something like 300lbs more than a 460 and only 210HP?

Honestly, I understand why the Cummins is such a great engine even with fewer HP than my 02' Honda Accord (220hp, 3L V6), but I wouldn't even consider that 3L V6 anywhere near as a powerful as a 5.9L Cummins... so I don't see why you're trying to use HP in an argument against the 400.

In the horsepower world, the 351m and 400 is most comparible to the 2L engine in my old CRV (was 150hp+), 460 and 5.9L Cummins is most comparible to the 3L in my 02' Accord (220hp.. the 03') so why are we using such large capacity engines that weight 3-5 times more than what they put in Hondas? Because HP shouldn't mean ANYTHING to us.


edit: and the water jacket issue is on the block itself, I think.. and IIRC it was solved when the 400 was released. Pre-400 351m blocks (76? I don't remember) did either crack at the head or water jacket in the block pretty commonly, especially when built. You also have oiling design issues with the 400.

 

If I recall, the 460 only weighs 50-75 lbs more than a 351M/400. And my point wasn't just the weight issue, it was the fact that since the 400 and 460 share similar mounts and trans bellhousing, why would you ever want a 400 instead of a 460 in anything? If you're going to swap from a small block, why not just go all the way to a big block?
My Cummins weighs 975 lbs, but it makes about 260 hp and 650 ft/lbs of torque, (at 1700 rpm) with the only mods being 4" exhaust, a Denny T fuel pin and timing and fuel adjustments on the injector pump. It also averages 20 mpg, city/highway combined, and that includes a lot of hard acceleration, because it's fun to drive something that big that takes off like a light performance car. But in actuality, the stock '91 Cummins makes EXACTLY the same 160 hp and 400 ft/lbs as a stock 400.. heh(although at about 1000 rpm lower) The big difference is, the Cummins was factory detuned to avoid destruction of the Dodge transmissions they were originally bolted to.

I understand what you're saying about the torque of the 400, but my main point was, if you're going to go through the work of installing a big block, why not just install a big block? If I saw a nasty built up 400, I'd still think it was cool, but I'd be thinking, "wow, that coulda been a 460!"

 

p.s. Honestly, If I was going to build for torque with a gas motor, I'd build a nice 300. I like inline 6s in trucks. Plus the swap is easy from a small block.

 

Choices, choices, 460s are way more expensive to buy and to mod than 400s... I personally would go with the 400, and try to address any oil starvation issues.

 

You think so? I figured the 460 is cheaper, since there's so many of them around. Good running used ones are still available and all, and the aftermarket offers great support for them. Why would you choose the 400 to build up? Just for the sake of doing something different? If so, I could understand that.