KJ Jones Senior Technical Editor
September 1, 2009
Photos By: KJ Jones
Rocco Acerrio of A.R.E. Performance and Machine in Simi Valley, California, measures the wingspan of Racecraft's aluminum engine plate, which we're using in lieu of traditional engine mounts in our Boss 340 '90 LX's engine bay. The 31-inch plate is -inch thick and made of 6061-T6 aluminum, and features the OEM offset for installing a 5.0-based engine in a Fox Mustang. When ordering engine or midplates, it's crucial to specify whether your particular application requires that the plates have standard factory or some other degree of offset in order to compensate for the rearend's offset. This ensures the driveline will be straight when the engine is installed.

While we know firsthand how difficult it is to battle with impatience when you're in the process of building a dream Mustang--be it for racing, cruising or showing--establishing and adhering to a project plan really is the best way to get things done. Your tech editor learned this valuable lesson while assembling our '86 T-top LX coupe a few years back. And Editor Turner, an honors graduate of the "Excel Spreadsheet School of Project Management," has been following the same practice with Fox 500, big Steve's '88 T-top LX hatchback that currently is in its assembly stage out at Paul's High Performance in Michigan.

As we start our third step in the construction of Boss 340, our Boss-engine-powered (302-based, fuel-injected stroker with canted-valve/Cleveland-style heads), '90 LX drag 'Stang, we're happy to report that progress has been smooth and steady, with tasks being 100-percent completed on the same day they're started (usually Saturdays).

This month's effort finally mates Boss 340's drivetrain and its related accessories with the actual Boss 340 Mustang's chassis. Sure, by rights, dropping an engine, transmission, clutch, and more in a street-driven Mustang is for all intents and purposes a slam-dunk procedure. However, given street 'Stangs' and dedicated race Mustangs' component differences and their complexities, we're not taking any chances with our drivetrain installation and have elected to do a dress rehearsal of sorts. A mock-up of the engine and tranny installment is our plan, and it will help us determine what, if anything, needs to be changed, or even made for the car, engine, transmission, and so on before it all can be set in place for good.

Of course, for our project, performing the mock-up brings an end to our streak of one-day installations. However, we strongly believe that making a trial run definitely is for the overall greater good. Nobody likes doing the same job twice, and especially not three (or more) times. But when it comes to building a race car from scratch, we think any race-car builder in the game will tell you that mocking up critical areas first is by all means a mandatory task for small- and large-scale projects.

Weights and Measures
With parts installed in mock-up fashion, we put Boss 340 back on Proform's digital scales (available through Summit Racing Equipment) to see how much weight has been gained, primarily by the addition of a drivetrain.

The 'Stang now stands at 2,369 pounds, which leaves us with about 530-or-so pounds to play with before we eclipse the sub-2,900-pound (without KJ) fighting weight that we hope to achieve for our Boss.

Checking and double-checking a Mustang's squareness up front is just as important as making sure the rear subframe is true, as we did when we swung Racecraft's fabricated 9-inch housing and suspension pieces underneath Boss 340 in our last installment on the project ("Bossy's Got Back," July '09). We decided to mount the engine in the same location that was established when a 351W engine was proposed for our chassis a few years ago. We used engine-plate and midplate tabs that were already set in place by Dave Rifkin and Ryan "Junior" Shostle of DS Racing. Both sets of tabs measure 32 inches from frame rail to frame rail.

Mock More
Boss 340 took a giant leap toward making weight (our proposed weight for the project 'Stang--without driver--is no more than 2,900 pounds) when we decided to swap the factory front bumper cover and a heavyweight 4-inch cowl hood with ultra-light fiberglass replacements from Schoneck Composities.

By sporting Schoneck's hand-laid, 4-inch cowl hood and '87-'93 Outlaw LX front fascia (the company also produces 'glass and carbon-fiber hoods and bumper covers for Fox GTs and New Edge Mustangs, as well as Fox fenders, wheel tubs, and dashes for '87-'04 Ponies) our 'Stang will be free of a lot of weight on its front end, which we can either say goodbye to forever, or replace elsewhere in the car if necessary (for chassis-tuning purposes).

This tryout came about simply because we couldn't stand looking at the two huge boxes anymore, and had to get some idea of how our race car will look with the Schoneck pieces. Trimming and fitting the fiberglass hood and nose will be handled by the crew at Raceskinz in Van Nuys, California, who are experts in this area and will make the parts look great on our project car.

Photo Gallery

View Photo Gallery