Diving Deep into the 351 Windsor: Ford’s Iconic V8 Engine

Howdy folks, Ed here. Welcome back to Bullnose Garage. The 351 Windsor Ford small block engine is one of the most venerable engines that Ford Motor Company has ever produced. Today on Bullnose Garage, I’d like to introduce you to mine and talk a little bit about this engine and why I chose it for my build.

So let’s start this video off right by introducing you to the donor. The donor was originally a 1994 F-150 with an E4OD automatic transmission, two-wheel drive, and of course, the 351 Windsor. What follows is most of the research I’ve done on the 351 Windsor in preparation for swapping it into my truck. Keep in mind that I gathered almost all of this information from places on the internet, and none of it is personal experience because I don’t have any. That said, I’ve tried very hard to fact check and verify my information as best I can. I hope that this information, put together in one place, is useful for anyone looking for more details or thinking about swapping or building this small block Ford engine.

So what is a 351 Windsor? The 351 Windsor, or 351W for short, is the largest of the Ford small block engine family. Ford Motor Company built them between 1969 and 1996. It’s a 90-degree V8 with an overhead valve train. The 351 corresponds to the number of cubic inches displaced by the stroke of all eight cylinders during normal operation. It’s also commonly referred to as the 5.8 liter for the same reason. The name Windsor comes from where the engine was produced in Ford’s Windsor, Ontario casting plant. Similar in size and shape to the very common 302, the 351 is a taller block. This allows for more piston travel in the cylinder, increasing the cubic inches to accommodate the increased displacement and increased power. The 351 block castings are beefier in almost every respect.

The Windsor is one of three engines offered by Ford in the 351 displacement. There was also the 351 Cleveland and the 351M, often called the modified. The Windsor engine is by far the most common and had the highest production numbers. Ford produced about 8.6 million units at the Windsor plant. It also tends to be the easiest to find aftermarket parts for due to its sharing many parts with a 302 small block.

So let’s go over some stats and measurements. The 351 Windsor has a displacement of 351 cubic inches, or 5.8 liters. The stock stroke of the engine is 3.5 inches, and the stock cylinder bore is 4 inches. It has a distinct firing order from the other Ford small blocks: 1-3-7-2-6-5-4-8 versus 1-5-4-2-6-3-7-8. Cast out of iron, the bare block weighs in at between 150 and 200 pounds, depending on the year. Blocks older than 1974 are heftier by 25 to 30 pounds due to having more metal in the casting. Prior to 1971, the deck height reached 9.48 inches, and after ’71, it changed to 9.503 inches. Something to make note of if you’re rebuilding one of these engines, since the deck height will affect the compression ratio and the valve piston head clearance.

The stock engine uses two bolts to secure the main bearing cap to the saddle, known as two-bolt mains. Stock, the compression ratio was around 11 to 1 in 1969. Emissions restrictions caused the ratio to move as low as 8.8 to 1 in later years. Early 351W engines produced a maximum of 300 horsepower and found their way into Mustangs, Galaxies, Cougars, Country Squires, station wagons, Fairlanes, and Torinos. Later years were also installed into trucks, vans, and marine applications. Later engines had lower horsepower numbers and higher torque numbers as a result of vehicle requirements and emissions.

So the 351 Windsor’s got an interesting history. Ford began casting the Windsor in 1969 and produced them up until 1996. Prior to ’75, blocks were cast using green sand molds and pneumatic packers or vacuum pressure. These methods worked well but caused some issues with mold core shifting. This meant that Ford required more material in the block to meet minimum specifications. After ’74, Ford used better molding techniques, eliminating the need for the extra material. While it’s true that newer blocks are weaker than older blocks because of this material deficit, 351 blocks are still the strongest small block available and should be able to handle any streetable horsepower numbers. Still, for this reason, builders sometimes covet 351 Windsor blocks from ’69 to ’74 if they’re looking for very high horsepower torque members.

In 1971, Ford extended the deck height from 9.48 inches to 9.503 inches to lower the compression ratio. In ’74, they added a boss in the right front of the engine for an air injection pump. Also in ’74, the oil dipstick moved from the timing case to under the left cylinder bank. Until ’76, the block used 16 bolt holes for the intake manifold, but Ford changed it to 12 bolts from ’77 onward. It should be noted that the 351 has larger head bolt holes than the 302. This means that the same heads will fit, but a 302 head will need to be drilled out to accommodate this if it’s being used on 351. A popular example of this is the GT40 head used on higher performance 302 engines being swapped into a 351 for higher flow numbers.

In 1983, Ford modified the rear main seal from the old two-piece design to a more modern one-piece rear main seal. Very late in the engine’s production, in 1994, the design changed again to accommodate roller lifters and camshafts rather than flat tappet lifters and camshafts. This change, only available in the final two years of production, makes these blocks highly sought after. Often these are just called F4 blocks due to the casting number or simply referred to as roller blocks.

So here’s a quick chart that I put together so that I could see exactly what gears which blocks had which features. That way, when I’m looking to go pull a Windsor out of a junkyard or another vehicle, I know exactly what years to look for for the features that I want. The second chart is one that I made to reference which vehicles these blocks go in. That way, when I’m looking on Facebook or Craigslist or even at a junkyard, I know what kind of a block that I’m going to get out of which vehicle in which year.

Ultimately, the best way to identify a 351 Windsor block is by using the Ford casting number. We can break down the beginning of Ford’s casting numbers into decade, year, vehicle or vehicle type, and engineering division. A casting that starts with C90E was built in 1979 because the C signifies the ’70s, and the 9 is for the last year of that decade. The 0 signifies that it was built for a Torino, and the E stands for engine. Castings that start with D are built in the ’70s, E in the ’80s, and F in the ’90s. My block is an F4TE, which means it’s a 1994 truck engine block. As I said before, F4 blocks are known as the roller blocks. That casting identifies them as having been built after 1994 when Ford switched to roller cam capable blocks. Note that Ford didn’t install roller cams in all roller blocks from the factory; many still utilize the old style flat tappet cams even though they are roller capable.

Ford produced two or three, depending on who you ask, different 351 engines during the same time period: the 351 Windsor and the 351 Cleveland. Every now and then, you’ll also hear about the 351M, also called modified, or might even hear about the 351 HO, or high output. What gives with all these different motors with the same displacement? Well, the Cleveland and the modified are both based on the same engine, which is entirely different from the Windsor. They called it Cleveland because Ford cast them in their Cleveland, Ohio plant. The Cleveland is part of the 335 big block engine family and was designed for more performance with better flowing heads and a stronger crank. Physical differences include a recessed timing chain and 8-bolt valve covers versus the Windsor’s 6-bolt covers. The bolt covers are the easiest way to tell if you’re looking at a Windsor or a Cleveland.

The 351M is closer to the Cleveland than the Windsor but is basically a de-stroke version of the big block 400, a different block altogether with a taller deck height than either the Windsor or the Cleveland at 10.297. The M also shares a bell housing pattern with other members of the 335 big block engine family, while the Windsor and the Cleveland both use a small block bell housing pattern. The 351 HO is just a Windsor engine with higher performance parts. It came with a four-barrel carburetor and a larger cam. Ford put HO engines in some trucks in the mid-’80s.

The Ford 302, or 5.0 liter small block, is in the same family as the 351, and it can often be hard to distinguish the two. The 351 has a taller deck height and subsequently longer stroke, which accounts for the difference in displacement. The 351 is also a heavier casting with more material, making it a stronger block overall. The crank and rod journals are also larger in the 351, adding to crankshaft durability. Many of the parts for a 302 are interchangeable to the 351. This includes heads, cam, lifters, water pump, engine mounts, timing chain, timing cover, and many other parts. As stated before, it should be noted that 302 heads have smaller bolt holes, so they’ll only fit a 351 if the holes are drilled out. Earlier versions of the 351, until ’76, incorporated heads with more bolt holes and larger intake ports than the 302, though the exhaust ports always remain the same size. The bell housing bolts to both engines are also the same. This means that a transmission that pulls up to a 302 will also bolt up to a 351. The firing order between the two engines is different, as is the oil pan intake due to the deck height harmonic balancer, except pre-’81 302s which share the internal balance of 351W and distributor.

There are several ways to tell the difference between a 351 and a 302 by visual inspection. The easiest I found is to look at the distributor mount height. The mount will be near flush to the top of the block on a 302, while the 351 has the distributor mount sunk below the top of the block by around an inch.

So does the Windsor make a good high-performance engine? Well, 351 Windsor blocks upgrade easily. A huge number of aftermarket parts exist for both the 351 and the 302. Popular upgrades are the heads since the stock 351 heads are mediocre at best, and other standard upgrade parts like the intake, cam, headers, and fuel delivery system. While the latest generation of 351 Windsors typically generated about 180 to 220 horsepower from the factory, adding a new set of heads, a larger cam, and some other aftermarket parts can get a Windsor with a stock stroke to around 350 to 400 horsepower easily. Stroking the engine by changing the crank and piston rods can increase the displacement to 383, 393, 408, 418, or 427. Doing so makes horsepower numbers as high as 500 to 600 easily attainable. Even higher numbers are possible with the correct aftermarket parts or power adders. The maximum horsepower attainable through a stock 351 Windsor is a matter of debate. Most agree that 500 to 600 is easily and safely attainable without risking damage to even the later standard strength blocks. Earlier high-strength blocks regularly reach 800 to 1000 horsepower without damage. When it comes to cracking an engine block, though, often it’s not the horsepower numbers but the sturdiness and quality of the parts and build that’s most important.

So can a junkyard 351W make a good performance engine? Well, in my opinion, the junkyard OEM block is a fine base to use for a 351 Windsor build, provided you’re not planning on putting out more than 600 horsepower and redlining RPMs all the time. Much more than that wouldn’t be streetable anyway. If you really want to race the block and send massive amounts of power through it, then it might be worth your time to hunt down a pre-’74 block for the higher strength. But there’s always the option of purchasing an aftermarket block. Purchasing an aftermarket 351 block can help you attain higher numbers without the worry of block failure. 1200 plus horsepower is not uncommon for an aftermarket 351 Windsor. Several reputable companies make aftermarket 351 blocks.

So why did I choose the 351? Well, my ’85 Bullnose houses a 306 from the factory, but a small block engine option existed for my truck. Because of this, I know the small block form factor will fit without an issue, unlike a big one. I wanted an engine that would bolt right into my Bullnose just to keep things easier for my first swap. The 306 shares the same bell housing bolt pattern as the small block engines as well, so I have the option to keep my transmission. Engine mounting points between the 300 and small blocks are also similar, with only the need to pull the mounts and purchase from the donor and bolt them into the Bullnose. I chose the 351 over the 302 because there’s no replacement for displacement. I’ve also read that the 302 is far easier to crack when running high horsepower numbers. I’m not planning on getting numbers that high in my first build, but who knows where I’ll be down the road. It’s also easier to get more horsepower for less money out of a 351, all else being equal, simply due to the larger displacement to start with. Finally, the Ford small block platform in general has a vast array of parts and aftermarket support, meaning I can build the engine just about any way I want to, and I plan on it.

Why did I get this particular vehicle as a donor? Well, obviously, it’s got the 351, which is the engine that I was looking for, and it was a fantastic deal. I managed to get this chassis with the engine, transmission, and pretty much everything you see here for right around 500 bucks. Now, the people that had it before were going to use it for some kind of a hot rod project, but it turns out that the frame is bent right here. Now, I don’t care about the frame; I’m getting it for the engine, so that works out good for me. And the fact that it’s a ’94 means that it’s a roller block. Now, a roller block means that I don’t have to go out and get link bar lifters or some kind of retrofit kit if I want to get a roller cam. It’s not that big of a deal; it’s only a few hundred dollars, but it does save you that money.

This chassis has been pretty much sitting here ever since I bought it. I’ve done a couple of things to it. I pulled the gas tanks off and sold those. I fogged the engine, which I’ve got a video about how to do that, and I sold the steering column because when I bought it, I also got the steering column and a complete wiring harness with ECU and everything. So I’ll probably end up selling that too because I’m going to convert this from EFI to carbureted, so I don’t need that stuff. That’s just more money that I can put in my pocket to go out and buy cool stuff for the engine.

The best way to determine what the internals of an engine look like without actually tearing it apart is using something like this borescope camera. Now I’ve got it hooked up to my laptop up there, but you can use a tablet or usually even a cell phone to do this if you’re sort of out and about and don’t have access to a big old laptop like I do. So we’re just going to go ahead and stick this inside and take a look and see what the cylinders look like. Oh, I’ll sit down. Hello! All right, here we go. It’s actually really hard to see with the reflection in there. Let’s try a different cylinder here. So you can still see some of the cross hatching on the cylinder walls. Let’s take a look at another one. It’s kind of hard to get an idea of what you’re seeing here sometimes, but obviously that’s the top of the piston. Looks like it’s in pretty good shape there. There we go. Now it’s really hard to see out here in the daylight. I’ll take a better look at this once I get inside and look at it on the computer, but everything looks pretty good from this angle here. Well, there we go. Ah, there we go! Yeah, see, I’m not a mechanic, but to me that looks pretty good for a used engine, so I’m pretty happy with that.

One of the problems with using a borescope like this during the daytime is that it can be really hard to see on a screen like a laptop screen or your phone screen. I mean, unless you see some really egregious damage, which shows up right away, and then you know what you’re looking at, some of the stuff that you’re looking for can be kind of subtle. So just keep that in mind if you ever take a borescope out to the field.

Well, there you go. That’s the donor and the 351 Windsor insider. I hope you guys enjoyed this video as much as I enjoyed making it. I did a lot of research on these engines, and I just love digging into the history and all the information about them. I was super stoked when I managed to get a hold of this one. I just can’t wait to tear it apart, see how it looks on the inside, and get it rebuilt and into the old truck and see how it runs. Man, there’s just so much to look forward to with this, and I can’t wait to get my hands dirty on it. Hopefully, I can do a good job and not blow it up or have any major issues, but you know, that’s part of the adventure too, so we’ll see how that goes. Hopefully, you guys will be along for the ride, and I can’t wait to get out more videos about it and see where this takes me. As always, if you have any questions, comments, concerns, gripes, internet ramblings, stick them below. Thanks again so much for watching, guys. We’ll see you next time.