Muscle Mustangs & Fast Fords
Demon 347 Short-Block Cylinder Assembly - Fast Ford Formula Part 1
Makin' Power With Bolt-ons, Boost, Or Both
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.
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.
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.