KJ Jones
May 2, 2013
Photos By: KJ Jones
SoCal Fox guru (and veteran street racer), Stevie Morrow, put his infinite mechanical talent and crafty wisdom into Project Cheaper Sleeper’s performance makeover. Our ’91 LX Mustang may look as plain as they come. But, believe us when we tell you, this street Pony offers a cool that goes far beyond what your eyes can see.

Thanks to a burgeoning aftermarket, our Mustang hobby has spawned fans of all of the popular EFI platforms over the years. The latest group of hard-core 'Stangbangers in the Mustang Nation is the ever-growing contingent of '11-'13 Coyote 5.0 GT owners who have taken to immediately modifying their new Ponies.

We're equally geeked about Coyotes and ecstatic about such strong enthusiasm for the latest ride. However, the Mustang scene's roots will always be based on the original 5.0s of '79-'95. Yes, Foxes truly make our hearts palpitate, especially the fuel-injected variety. Based on the "more Fox coverage" emails and Facebook messages we receive, it appears a number of you concur.

Those of you who pay close attention to our tech activity are aware of our most-recent Fox Rod effort, Project Cheaper Sleeper. Founded on a '91 LX hatchback, it began when your tech editor picked up the stocker for the insanely low price of $1,000 ("Beg, Borrow, and Deal," Jan. '13, p. 74).

These days, stock or lightly modded Mustangs of all genres are readily available for low-dollar resurrections of all sorts.With this in mind, our strategy for Cheaper Sleeper is to upgrade the Pony with new and used bolt-on performance hardware on the cheap. Certainly it will have street/strip capabilities, but we've resisted the urge to add beauty to the brawn. That's the other part of the plan—keeping our 'Stang looking as unassuming as a good street sleeper should.

Our longtime engine specialist Rocco Acerrio of A.R.E. Performance & Machine [(805) 583-0602] and Jack-of-all-Mustangs Stevie Morrow from Stevie's Garage [(805) 578-0605] are the dynamic duo bringing together all of our project's proposed trickery. It starts with the undercover engine that you'll read about in the following pages.

Yes, the makeover of our 'Stang's high-mile, stock 5.0 is at the front of this effort. However, this upgrade evolved beyond the initial plan of simply replacing the top half with a set of Explorer/GT-40 iron cylinder heads, intake manifold, and an aftermarket camshaft.

When you look at the project's bigger picture detailed through the images and comments in sidebars surrounding the engine info, Stevie's knowledge of Fox 'Stangs, masterful craftsmanship, and overall production talent, definitely were the keys to creating Cheaper Sleeper with the high degree of stealthness that we envisioned from the beginning.

Make sure you give this segment a thorough read, as it lays the foundation for our next installment which will focus on tuning, dynoing, and drag racing our project Fox.

Horse Sense: When it comes to cost and projects like this being "cheap," we must emphasize that while many of the parts we're highlighting on our Pony are new, that doesn't mean these awesome Mustang pieces are attainable only by buying new parts. Keeping costs low for new equipment, or perfectly fine used gear, is all about having patience, doing good research, and acting quickly when a great deal comes your way.

The first order of reconstructive business was extracting Sleeper’s high-mileage virgin 5.0-liter engine. In past reports, we’ve recommended taking advantage of the opportunity to clean up the engine compartment, by rattle-can painting it or installing Scott Rod Fabrication’s dress-up panels. While it was tempting to go this route, we limited the cleanup to a good power washing, so as to not draw too much attention to the fresh engine.

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Autolite’s Jay Buckley recommends XP103 Iridium spark plugs for stock or moderately modded pushrod 5.0/nitrous engines with iron heads that won’t see more than a 150 shot. If you’re bold enough to shoot a bigger gun with a stock-block engine setup like ours, AR-92 plugs are colder and about the best bet for taking that kind of chance.

Stealth Running Gear

The factory AOD transmission is a prime candidate for failure in Mustangs that undergo substantial performance mods, and then are subjected to somewhat severe usage on the street or at the track. Our friends at Performance Automatic turned us on to a turnkey transmission package that remedies this (available exclusively through Latemodel Restoration). So into Cheaper Sleeper it went.

The trans unit in PA's Street Smart kit is designed to hit hard on the street, and more importantly, stand up to hard runs on the quarter-mile by simply dropping the gear selector in Second and letting the unit do its thing. We like this idea, as it eliminates having to do the dreaded shuffle that's necessary when trying to manually-shift AOD transmissions.

Our sleeper's additional driveline support comes in the form of an 8.8 rearend that Stevie Morrow assembled with Moser Engineering's direct-replacement, 31-spline axles and all-new Wavetrac differential. Per our first segment of this series, the original 8.8 received a set of 3.55 gears as an enhancement over the OEM 3.27s. A used-but-like-new 3.73 gearset came our way thanks to the PSCA's Classifieds board. The 3.73s will be the ratio we ride with going forward as it has optimal gearing for setups like Sleeper.

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Our Pony’s undercover engine mod pretty much mandates that attention be paid to the transmission, as the stock unit simply will not support too much of a power/torque increase. When you consider the cost of a rebuild, a better bet is going with a brand-new setup from Performance Automatic that’s designed specifically for Fox Mustangs that are hopped up to the 450-rwhp range. The Street Smart Package (PN PASS53103) is as all-inclusive as a transmission kit can get, featuring everything shown in the photo: AOD transmission, hardened ¾-inch input shaft, street/strip valvebody upgrade, 2,400-stall converter, TV cable, block protector, dipstick, shifter linkage, and SFI-approved flexplate. The cool thing about this set is that everything is brand-new and a direct, no-hassle replacement for all of the OEM trans hardware. For ‘Stangbangers with the know-how or gumption to take on a DIY rebuild, the trans unit’s internals (extra-wide overdrive band, Kolene Steels, diode sprags, extra 3-4 Red clutches, bushings, washers, seals, and gaskets) are offered as a Max Performance Kit (PN PAKT53701 A0D-90-93), which does not include any of the finishing hardware.

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Managing Expectations

While Cheaper Sleeper's driveline is filled with stealthy little upgrades, we're equally as excited about some of the tricks that are going on in the 'Stang's engine management and power adder.

As Fox veterans know, getting factory EEC-IV engine management to play nicely with a slew of aftermarket engine upgrades—especially a completely new fuel-injected stroker engine with a power adder—requires manipulating various fuel and timing tables, which is achievable only with chips, piggyback processors, or standalone ECUs. Many of the standalone systems, while excellent, are oftentimes a bit too advanced for some setups. Enter Modotek, an electronics- division of Cometic Gaskets that has created a plug-and-play management system for modified '86-'93 EFI Mustangs that serves these Ponies in the same capacity as the standalones. The BlackBox 2.0 ECU ($1,349) connects directly into a Fox 'Stang's stock wiring harness, and allows users to precisely tune engines for maximum performance with a laptop.

As the undisputed most affordable power adder, nitrous oxide is the steam enhancer of choice for Project Cheaper Sleeper. For the nitrous setup, Stevie Morrow pulled all of his old-school knowledge out of mothballs, taking various NOS-brand bits and creating a 150hp nitrous kit that we anticipate will hop things up quite nicely and make our undercover LX a really fun Mustang.

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The finished engine looks pretty plain-Jane, doesn’t it? Down below, Bassani short-tube headers and a full exhaust system with an X-shaped crossover that includes high-flow catalytic converters and stainless mufflers let out the growl. Now you know the secrets. Try one or try ‘em all on your low-buck Mustang project. Hop-up efforts like this are a lot of fun, and they definitely prove that pretty and expensive don’t always apply to cool Ponies. 5.0