Demon Engines supplied a 347...
Demon Engines supplied a 347 stroker kit that included a 3.4-inch steel stroker crank, 5.4-inch forged rods, and 4.030 forged (flat-top) pistons from Probe Racing.
When it comes to modifying your 5.0L Mustang, there are several routes you can take to improve performance. They include increased displacement, basic bolt-ons, boost, and, of course, nitrous oxide. Only your bank account will determine whether these avenues are explored alone or in tandem.
It's every bit as easy to add basic bolt-ons to your stock 5.0L as it is to a stroker version; ditto for forced induction or nitrous oxide. Basic bolt-ons are the most popular due to the low cost, but it takes a great many bolt-ons to equal the power offered by a stroker short-block or a power adder.
The Demon Engines reciprocating...
The Demon Engines reciprocating assembly was stuffed inside a late-model 5.0L Ford block to produce a 347 short-block. Note the use of Fel-Pro 1011-2 head gaskets and ARP head studs. These are a necessity when adding boost to any 5.0L.
In terms of bang for the buck, it's hard to beat a simple nitrous system, but many don't like the hassle of switching the bottle, dealing with refills, or the lack of a linear power curve. When it comes to boost, where you begin your adventure will help determine your eventual destination. By this we mean that adding boost from a turbo or blower kit to a stock and modified 5.0L motor will have decidedly different results. Actually, the results will be quite similar in terms of the percentage gain, but the end results will be substantially higher on a modified
At MM&FF, we decided to combine a number of different performance routes- including displacement, bolt-ons, and even forced induction-all in one test. The idea is to illustrate the power gains offered by changing the heads, cam, and intake on a typical 5.0L assembly.
The 347 short-block was topped...
The 347 short-block was topped off with factory E7TE 5.0L iron heads. Hardly ideal, the stock heads would prove to be quite restrictive on the stroker. We also installed the stock 5.0L hydraulic roller cam. The hydraulic roller portion is always welcome, but the factory 5.0L cam limited the performance of our test motor.
Rather than run the test on a stock 5.0L 302, we decided the readers would be better served if we tested the results on a 347 stroker assembly supplied by Demon Engines. The Demon 347 featured the usual reciprocating assembly consisting of a 3.40-inch steel stroker crank, matched with a set of forged 5.40 inch connecting rods and forged flat-top pistons from Probe Racing.
The pistons featured valve reliefs for inline-valve heads, which allowed us to successfully replace the factory 5.0L cam with a wilder XFI unit from Comp Cams. We chose the 347 stroker since most 302 builds include a displacement upgrade. The stroker assembly makes good financial sense since the cost of building a 347 is really no different than building a 302 or 306. Of course, that changes if you already have a 302-but fear not, as the modifications and boost work equally well on the smaller 302.
All of our testing was performed...
All of our testing was performed with a set of Hooker 1 3/4-inch Super Comp headers feeding 18-inch collector extensions.
We relied on the FAST XFI...
We relied on the FAST XFI management system to control the fuel supplied by a set of FAST 36-lb/hr injectors.
Ignition chores were handled...
Ignition chores were handled by an MSD billet distributor and Pro Comp plug wires.
Keeping our test motor cool...
Keeping our test motor cool was a Meziere electric water pump. Use of the electric water pump allowed us to run the 5.0L without any accessories. This made head and cam swapping much more convenient.
The stock heads and cam were...
The stock heads and cam were topped off with a GT-40 upper and lower intake. Equipped with the stock components, the 347 produced 307 hp at 4,700 rpm and 401 lb-ft at 3,300 rpm.
First on our list of performance...
First on our list of performance mods was a set of RHS aluminum heads. The RHS aluminum heads should be considered for sheer weight savings alone over the heavy factory iron heads.