Muscle Mustangs & Fast Fords
Ford 351 Windsor Engine Build
Our Budget 351 Shoots For Competitive Power Levels While Maintaining Daily Driver Manners.
So you've been driving your Fox-body or SN-95 Mustang for a few years now, and you realized that over the course of your 45-60 minute commute, you've grown tired of the lumpy camshaft's propensity for surging and bucking, which is due, thanks in part, to the relatively ancient computer that can't make sense of the high-overlap camshaft's shenanigans. But common sense strikes and you also realize that you cannot live with stock 5.0L power. What does one do in this predicament? Build a 351 Windsor engine.
With the Fox-body's weight bias already pretty fubar with the 5.0L, adding some 60 extra pounds to the front certainly won't help in this department, but you can cancel out much of that extra heft by using aluminum cylinder heads, and a tubular front K-member and A-arms.
It's not a necessary expense though. If you're just looking for that extra surge of power when getting onto the freeway or interstate, and not planning on carving up the turns, you probably won't notice the weight
What the 351 offers over a 5.0L or 302-based stroker is a better rod ratio, a stronger block, and the ability to go up in displacement for even more power and torque. The sizeable increase in displacement will also offer more average torque and horsepower than a 302, and will allow us to do it without a lumpy cam profile. That is our goal for this budget-minded buildup.
Looking across the street at what the General offered in late-model F-bodies, the 346ci LS1 offered up some 325 hp (350 in the Corvette with a better exhaust), while the LS6 (346 ci) produced up to 405 hp thanks in part to better heads, intake, and camshaft specifications. We plan to put our Street Smart Windsor somewhere in this mix. While 400 hp would be very nice, we are somewhat limited with our camshaft options due to the stock pistons in the short-block.
Whereas the LS6 lifted the valves 0.550 inches, we'll be limited to about 0.500. One could make this up with the duration and lobe separation angle, but we intend to keep a stock idle and driveability characteristics, similar to the LS engines. If you want to add the hot cam and deal with the reduced driveability, then have at it, but a smooth idle and stock driveability are high priorities for this buildup, and the increased displacement should offer plenty of power and torque for us to have fun with on our daily commute.
Most people aren't going to sink a ton of money in an engine and not have it maxed out power wise, so we felt it was necessary to keep the costs down wherever possible, starting with the short-block. Advertised for just $999, Latemodel Restoration Supply's (LRS) budget 351 starts with a late-model factory 351ci two-bolt-main engine block that was sent out for a stock rebuild. The rotating assembly is all factory cast parts, from the crank to the rods and pistons. There are no magic speed parts here-just your basic Blue Oval truck parts and a rebuild that should last 100,000 miles or more. It's definitely budget friendly, and will allow you to spend more money on the cylinder heads and camshaft, where it counts the most.
Dropping a 351W into a Fox or SN-95 chassis isn't anything new, and a number of companies offer all of the parts you need to bolt it right into your Mustang without too much drama. Ford Racing Performance Parts, among others, offers an oil pan, oil pump pickup, and dipstick combination just for this application. The company also offers the brackets necessary to make your factory accessory drive system bolt right up. While ordering you short-block from LRS, you can order all of these parts as well. Other 351-specific parts you will need are an intake manifold, distributor, and exhaust headers.
A stock truck EFI distributor will get the job done if you can find one, otherwise you'll have to look to the aftermarket. Pro Comp, Accel, and MSD all offer a drop-in unit that utilizes the factory TFI ignition module. Headers for the 351W can be found in both shorty style and long-tube versions; Trick Flow Specialties and Edelbrock both offer 5.8L intake manifolds that are designed to work with factory fuel injection systems. There are also carburetor manifolds that have been converted for fuel injection, but we're looking for something that resembles the factory intake manifold.
For cylinder heads, we looked to Racing Head Service and the company's 200cc Pro Action aluminum cylinder head. The Pro Action series is designed for high-performance street and racing applications, and the 200cc intake runner will allow the 351 to breathe easily without losing too much port velocity. This head can be had with either 58cc or 64cc combustion chambers and in 0.0560- or 0.600-lift spring packages. We went with part number 35012-2, which specifies a 58cc chamber and 0.600-inch-lift springs for use with a hydraulic roller camshaft. While this head flows as much as 286/202 cfm at 0.700-inch lift, at our limited range of 0.500, it still flows 277 on the intake and 193 on the exhaust. Should we change out the pistons and pop in a larger camshaft, the heads will be able to offer plenty of airflow to support the better breathing valvetrain.
Atop the RHS cylinder heads will be a set of Comp Cams all-new Ultra-Gold aluminum rocker arms in the factory 1.6:1 ratio. Designed specifically for high-performance street and race engines, Comp's Ultra-Gold rocker arms are precision CNC-machined to strict tolerances, and are designed to fit an assortment of rocker-stud diameters in a variety of rocker ratios for small-block Ford applications. They are also designed to withstand extremely aggressive spring pressures and valvesprings with as much as a 1.650-inch O.D. They also come with a lifetime warranty.
The camshaft will be the most optimized piece of the puzzle in this build, and probably the most expensive item as well since it will be a custom grind. Most off-the-shelf aftermarket camshaft grinds feature far too much duration and lobe separation than a stock-style cam, and right now, we plan to use a modified version of Comp's 35-413-8 hydraulic-roller grind, which offers a split duration pattern of 212/218 degrees at 0.050, and a valve lift of 0.513. We will change the lobe separation to a more idle and vacuum-friendly 114 degrees, as opposed to the standard 110. If time and interest permits, we may pull the pistons and swap them out for a set with bigger valve reliefs down the road, so we can get somewhere closer to 0.550-0.570-inch lift.
With the heads and camshaft chosen, we're looking at two options in particular for our 351 Windsor build-the Trick Flow R-series intake manifold, and the Edelbrock Victor 5.8 intake manifold. The Trick Flow R-series for the 351 features 13.3-inch-long runners, a 2.00x1.20 port size at the head, and an 11.5-inch overall height. With a 75mm throttle body, Trick Flow claims the R-series will support a rev range of 1,500 to 5,500, but stepping the throttle body up to a 90mm piece will broaden the rev range to 2,000 rpm to 7,000 rpm.
The Edelbrock Victor Ford 5.8L EFI intake is designed to work from 4,000 to 7,500 rpm, and is capable of supporting over 700 hp. The Victor Ford 5.8L features Edelbrock's air-gap design, which isolates the intake charge from the engine heat that is present in the lifter valley. The manifold's runners feature 2.0x1.20-inch exits with a 12.5-inch runner length.
We're also considering Trick Flow's Box R-series intake manifolds for Ford 351 Windsor, which cuts the runner length to 11 inches to support a rev range of 2,500 to 7,500 pm. Though our 351 is substantially larger than the 302 it will replace, it's probably not enough cubes to keep the air moving efficiently through the box design. We may test it down the road just to illustrate how it works in this rather mild application.
So we've laid out the plan for this street-smart Windsor. Next month, we plan to assemble it and have it on the dyno to see how we compare to the General's (or rather the government's) latest technology, and after that, who knows. Maybe we'll stroke it, or throw a thumping camshaft in there just to please the masses.