When it comes to 5.0-liter Mustangs, there is a seemingly unlimited supply of aftermarket parts to make those 302 cubic inches as efficient as possible. You can bolt on top-end kits, better-flowing exhaust, and even power adders. But what if you like making as much power as possible without the help of a supercharger, turbo(s), or nitrous, and 302 cubes just isn't enough? The simple answer is an increase in displacement.
There are three major ways to increase displacement. First is cylinder boring. Oversized bores can increase displacement of an 8.2-inch-deck Windsor (302 ci) to 310 ci (0.060-over with a stock block). This is usually done out of necessity during a rebuild or when doing a stroker kit. If an engine failure or wear and tear scores the cylinder walls of the block, boring and/or honing can correct this. Another reason to bore is if you're racing in a sanctioning body that allows a maximum displacement, and you're trying to increase power output within the rules.
Another more popular way to increase displacement is by increasing stroke. By using a "stroker" crankshaft, the piston is pulled farther down the bore, increasing displacement. Stroker kits utilize a shorter, larger diameter piston and longer rods. This is an effective way to increase displacement without going as far as an engine swap.
Engine swaps are the third and most obvious way to increase displacement. For Fox-body Mustangs, the 351W swap is common, and there are many parts available to make it easier. The 351 beats out the 347 by a few cubic inches, but there are other issues, like hood clearance and accessory mounts, due to the taller deck of the block. There's always the big-block swap, but that's another story in itself.
On both our 363 short-deck...
On both our 363 short-deck and 363 tall-deck engines, we will be running Edelbrock intake manifolds with a Holley carburetor (not yet determined).
The first thing to understand before we start this comparison is the difference between a short-deck Windsor and a tall-deck Windsor. Short-deck refers to an 8.2-inch-tall deck, 302ci engine. The larger 9.5-inch Windsor is the base for the 351W. (There is a rare 9.2-inch-deck Windsor as well.) The two blocks are very similar, except the tall-deck block extends 1.3-inch higher than the short-deck. Difference in stroke (3.500 inch) and rod length allows the tall-deck engine to displace 351 ci with 4.000-inch pistons. A 5.0L 302 utilizes the same 4.000-inch pistons, but only has a 3.000-inch stroke. The 351W utilizes larger 3-inch mains, but also weighs in about 25 pounds heavier than a 302.
We will run both engines with...
We will run both engines with street-style dual-plane air gap intakes, and then both with Victor Sr. single-plane intakes.
To achieve more stroke out of a short-deck block, a stroker crankshaft pulls the piston farther down into the bore, requiring some machining of the block. A typical 347 stroker utilizes a 3.400-inch stroke and 4.030-inch pistons. That has been the standard for 302-based big strokers for years.
With Ford Racing Performance Parts' new Boss block, the same stroke can be combined with 4.125-inch bores, bringing displacement to 363 ci. To showcase this and provide its customers with a larger-cube engine in the same package as the 302, FRPP released a line of 363 engines. If you have a running 5-liter in your Mustang now and already have aftermarket heads, intake, and camshaft, then you could opt for the 363 short-block (PN M-6009-363; $4,899). Utilizing the Boss block, the FRPP team machines it to clear the stroker crankshaft and 4.125-inch pistons.
"The 363 was the natural next step for our crate engine lineup," says Jesse Kershaw of FRPP. "With the Boss 302 block, it makes sense to go bigger bore—it's free horsepower and torque! The 4.125-inch bore of the 363, as compared to a 347 engine with 4.030-inch, unshrouds the valves and really lets the engine breathe with 2.02-inch intake valve heads like our Z304."
Forged crankshaft and I-beam rods from Scat actuate forged-aluminum pistons from Mahle. The short-block is internally balanced and designed as a direct bolt-in part, though some parts, like head bolts, must be upgraded. The Boss block utilizes four-bolt mains and increased cylinder-wall thickness, making it far superior to a stock block in its ability to handle high-horsepower applications.
Comp Cams is custom-grinding...
Comp Cams is custom-grinding camshafts for both 363ci engines.
It is also providing us with...
It is also providing us with the rest of the valvetrain, including rocker arms, pushrods, and so on.
Both engines will be run with...
Both engines will be run with FRPP's Z304 cylinder heads. These are the un-ported pieces...
.... but still utilize 204cc...
.... but still utilize 204cc intake ports and 2.02/1.60-inch valves--plenty for our application and good enough for the Z363 crate engine to produce 500 hp.
Since some say the tall-deck engine is the way to go and others swear by strokers, we're using this opportunity to put the 363 stroker against an equivalent 363ci tall-deck Windsor (0.060-over).
We've procured a 363 short-block and two pair of Z304 heads from FRPP--one set for the tall-deck engine and one set for the short-deck. FRPP also sent us a Boss 351 block, which we will bore 0.060 over to bring displacement (with a stock stroke of 3.500) to 362.493--we'll call it 363 for simplicity. Edelbrock is providing us with as-equivalent-as-possible dual-plane Air Gap intake manifolds for both engines, as well as single-plane Victor Sr. intakes.
Concerning camshaft choice, it wouldn't be fair to the tall-deck 363 to use the same camshaft that the Z363 crate engine uses. And it wouldn't be fair to either engine to have a custom camshaft ground that benefits both engines. Instead, we called Comp Cams to grind custom cams for each to maximize power and torque within our rpm range. Comp is also supplying the rest of our valvetrain components, like lifters, rocker arms, and pushrods--the same parts for both engines--to make this as fair as possible.
We realize someone probably won't go through the trouble of building a 0.060-over 351W for funsies, but it's the best way for us to make this comparison fairly. So which one do you think will make the most power? The most torque? Which one will make the most in the low-to-mid range? What about mid-to-high range? Send us your guesses to marc.christ@sorc.com.
Next time, we'll get our short-deck 363 together, run it on the engine dyno, and introduce the components of our tall-deck 363.
FRPP is also offering complete crate engine versions of the 363, which are available in either front sump (PN M-6007- Z363FT; $8,595) or rear sump (PN M-6007-Z363RT; $8,595). These come complete from valve covers to oil pan, and are ready to drop into your Mustang, pickup, or street rod.
Rated at 500 hp at 6,500 rpm and 450 lb-ft of torque at 5,300 rpm, this engine is designed for street and/or strip use. The torque curve delivers over 390 lb-ft of torque from 3,500 rpm to the 6,500-rpm redline. At 10.0:1 compression, the Z363 even makes that much power on pump gas.
Using the same 363 short-block as a base, FRPP adds its Z304 cylinder heads (PN M-6049-Z304DA; $1,049/each), roller rockers, FRPP damper, water pump, valve covers, 7-quart oil pan, and a specially ground camshaft (0.580/0.602-inch lift; 232/240-degrees duration at 0.050-inch).