Steve Baur
Former Editor, Modified Mustangs & Fords
May 21, 2010
Photos By: Justin Cesler

As popular as the 5.0L pushrod engine is (we actually have to separate it from the new overhead-cam engine now), old school hot-rodders know that bigger cubes means bigger power. If a 302 is good, a 351 must be better, right? They're not wrong, and we intend to show just that with our Street Smart Windsor build.

Sure, your author takes his hits around the office from those who make fun of his need to have stock driveability, but then again, none of them drive as much (104 miles every day). After living with lopey cams, surging throttles, and bucking drivetrains, it's time to build a better mousetrap.

Last month, we set the goal for 350-400 flywheel horsepower with a stock idle, and we decided to use a budget 351 Windsor short-block from Latemodel Restoration as the foundation. The $999 Windsor wonder doesn't feature one trick or high-performance part, but it offers cubes, a good rod ratio that will ensure longevity, and the ability to go even larger in displacement if needed.

Right now you're probably thinking, what kind of Mustang enthusiast is satisfied with a mere 350 hp when there are 600-rwhp GT500s running around? Well, not all of us have $35,000 for a GT500 and another $6,000 for mods. And you'd be more than surprised at how fast a 3,100-pound car is on the street with 350 hp and as much torque. Just ask any Corvette Z06 owner. During the project Stolen Goods Cobra build, your author also realized that naturally aspirated street power is trouble free, and 350-400 hp in a Fox-body Mustang is more than enough to overpower the tires at any given moment. You can do this with a stock idle, saving yourself a few dollars, and gray hairs too.

Last month we talked about our options and possible choices for engine components aside from the aforementioned short-block from LRS. We went ahead with the RHS cylinder heads. RHS's Pro Action 200cc inline valve heads offer enough airflow to support our 359-cube motor. According to the markings on our pistons, our short-block has been bored 0.040-inch over on the cylinder bores. When combined with the 3.500-inch stroke, that equates to 358.93 ci.

We also went with Comp Cams' Ultra Gold aluminum roller rocker arms and the custom camshaft grind that we detailed. Duration checks in at 212/218 at 0.050-inch lift, with lift figures of 0.513 inch on both valves. Cut with a 114-degree lobe separation angle, this grind should give us the smooth idle we want, while maximizing the valve lift for our combination. After talking over the intake manifold choices and specifications with Comp Cams' Chris Mays, we went with the Trick Flow Specialties R-Series EFI manifold for the 5.8L engine. We also specified the 90mm throttle body opening so we could try larger throttle bodies down the road, but for now, we'll be using one of Trick Flow's 75mm units.

An area that we didn't cover in the first installment is the mass air meter and intake tract. For that, we turned to induction guru Rick Anderson at Anderson Ford Motorsport. We often consult with Mr. Anderson: His numerous years of experience in the Mustang hobby, and countless hours on the dyno and at the track, have taught him what works and what doesn't. To fulfill Street Smart Windsor's airflow needs, he recommended one of Anderson Ford Motorsport's Power Pipes; he also recommended Abaco Performance's DBX97b programmable mass air meter.

The DBX97b mass air meter measures-you guessed it-97mm, and features a bell-mouthed entry for maximum incoming airflow. All Abaco meters are digital-based, and can be programmed to meet your engine's airflow and fuel injector requirements. They also feature a patent-pending digital response filter that helps filter out "noise" in the airflow signal, which is said to improve driveability-there's that darn word again. The meter doesn't suffer ill effects from clocking the housing in a certain orientation, thanks to its multiple sensing elements. You can also move it from Mustang to Mustang just by switching the harness and the program inside the meter, which holds up to 10 different programs.

What stays and What goes?
If you're pulling parts from your 5.0L, here's what you can reuse: the timing cover can be swapped, and since the water pump bolts directly to it, you can just leave that on there when you pull it off the motor. Many people feel that upgrading the water pump is a good idea in any high-performance application, especially with a Windsor engine, but for our build, we think the stocker will work just fine. The timing pointer, alternator, and bracket all make the change without issue. The other side of the engine is where you run into problems.

With driveability being a driving factor in all of this, naturally we will want to keep our air conditioning and power steering intact. To accomplish this, the easiest thing to do is call your nearest Ford Racing Performance Parts dealer and order part number M-8511-B351, which will get you a pair of brackets that allow you to bolt your A/C compressor and power-steering pump to the taller Windsor block. If you're skipping the A/C and just want power steering, order part number M-8511-A351; If you're sticking a 351 in an SN-95, skip both of these and bolt the components directly on.

We ordered our brackets from Holcomb Motorsports in Lumberton, North Carolina. Holcomb has long been known in the Mustang hobby as an engine swap specialist and offers everything you need to make it happen. You'll also need a different serpentine belt; we'll share our part number once we have everything mocked up. Note that belt length varies depending on pulley choice.

The harmonic balancer and flywheel can be shelved, as you'll need pieces that feature a 28-ounce balance weight, as opposed to the 5.0L's 50-ounce heft. We had one of FRPP's M-6316-C351 SFI balancers left over from a previous tech article and opted to use that, though for a budget build like this, a stock 351 balancer would work just fine. You'll have to check your crank pulley alignment, as you may need a spacer to keep everything on the same plane. FRPP has those as well. Whatever balancer you use, remember that your 5.0L crank pulley has four bolt holes. You can reuse it provided you get a balancer with four, rather than three holes.

Most 5.0L cylinder heads will fit on a 351 Windsor, but you'll have to make sure the bolt holes are drilled out, as the 351 uses half-inch bolts/studs whereas the 5.0L uses 7/16-inch pieces. Yes, Ford put the little GT-40 heads on the 351 in the Cobra R and SVT Lightning, but there are so many better options out there now that it just doesn't make sense to do that unless budget weighs far more heavily than the ultimate performance goal. Remember you're dealing with a 351ci (359 in our case) engine that requires a lot more air than your stock or near-stock 302 engine, so most of you are going to want heads with an intake runner no less than 180-200 cc in size.

Since all of these cylinder heads fit 302s as well, the lower intake bolts are all the same and can be reused. The 5.0L headers can be reused if you have a custom midpipe fabricated, but companies like BBK Performance make it easy for you by offering shorty swap headers that bolt right up to your existing X- or H-pipe. Yes, you can get a long-tube header and midpipe assembly as well, but we went with the shorties for their ease of installation, maintenance, and the relatively mild power potential of our combination. Beyond that, your 5.0L bellhousing and clutch will bolt right up, but you'll need the aforementioned 28-ounce flywheel to connect the dots. These are readily available most anywhere, but we went to Summit Racing Equipment in Tallmadge, Ohio, for a Ram 157-tooth, billet-steel flywheel (PN RAM-1527).

Summit Racing also provided us with a number of other items that you'll see throughout the build. With three warehouses scattered across our great country, you're just about guaranteed to get your high-performance goods within a day or two of ordering. Since one of the warehouses is based in Atlanta, we got one-day turnaround service to our Tampa, Florida, office.

With that said, Summit Racing provided us with the needed 5.8L EFI distributor-this one came from Mallory Ignition (PN MAA-7968704). Summit, MSD, Accel, and Mallory all offer the correct distributor for the fuel-injected 5.8L engine, and they use the factory, or provided, high-performance aftermarket TFI module that connects to the factory wiring harness. We are also using Mallory's high-performance spark plug wires (PN MAA-949M). The cheap way out of the distributor game is to find one from a '93-'95 SVT Lightning, or later-model 5.8L fuel-injected truck or van. You need to swap out the distributor gear for a steel one if you plan to use a hydraulic-roller camshaft with the Ford distributor. The factory stuff is very good, even with a bit of miles on it, but if you find yourself considering a new one, go for the flashy billet aftermarket stuff. It's great eye-candy at the car show and they work excellent as well.

From the folks at FRPP, we received the M-6675-A58 oil-pan swap kit, as you'll need the new pan to fit the Windsor engine in the Fox. The FRPP kit includes the 5-quart pan, the oil-pump pickup and mounting stud, as well as a new dipstick and sheath. While you're at it, order yourself an M-6605-A341 oil-pump shaft from FRPP, and a new standard-volume oil pump for a 351W from the local parts store.

Motor mounts aren't so much of an issue as they are a preference. With the increase in deck height as well as overall height of the 351W, your new powerplant is bound to require an aftermarket cowl-induction hood to clear the intake manifold. There are ways to combat this, and one of them is to use drop motor mounts like those from Holcomb Motorsports (PN OT6000351D). Holcomb's mounts are a solid-steel design, so you are going to feel a bit more vibration in the car, but if you keep the stock rubber or urethane transmission mount, it will help. Our stock idle should help quell vibrations as well.

Keep in mind that oil pan clearance to the K-member and steering rack can be an issue, though it isn't when using the FRPP oil-pan swap kit. Another idea is to use an aftermarket tubular K-member. These can offer additional pan clearance, as well as lower mounting points for the mounts. We've seen a carbureted Windsor fit beneath a stock hood using both of these tricks, but haven't spotted an EFI setup that does. The motor mounts will help, though.

Since we're using a production 351W roller block, your roller lifters and lifter spider in the valley can make the jump to Windsor speed, as the bolt holes are already in the block. If you don't have these parts to carry over, Comp Cams offers a hardware kit (PN 35-1001) that includes the spider and hardware. If you're using a non-roller block, Comp has you covered as it offers retrofit camshafts and tie-bar roller lifters to get the job done.

Fuel system changes are minimal. Stock 5.0L fuel rails can be used, but you'll need to cut the plastic crossover lines, and get some approved high-pressure fuel line and clamps (the clamps are special too) to allow the rails to sit properly on the wider 351 lower intake manifold. With more airflow comes a need for more fuel, however, so an in-tank fuel pump upgrade is a must, as well as 30-lb/hr or larger fuel injectors.

With all the details covered, you should be well on your way to shoehorning that Windsor between the frame rails of your Fox-body. Most swaps, including this one, can be a big undertaking-but hopefully we've made it a bit easier now that we've laid everything out for you. Check back next month as we drop this Street Smart Windsor into our latest Fox-body hulk and pound some Dynojet rollers for the details. And keep reading because we have a bunch more swaps in store.