Probe Outfits Our Boss 340 With High-Rev H/C/I Gear From AFD, Comp Cams, And Wilson Manifolds
Air Flow Dynamics' SP4VS Extreme Complete Competition cylinder heads and Wilson Manifolds' new "Boss 302" intake manifold are the crown jewels for the all-out, drag-race edition of our Boss 340 project engine. The upgrade pieces are much more aggressive and race-oriented than the Edelbrock (351 Cleveland 2V heads)/modified-OEM '69 Boss intake package that sat atop Version 1.0. They should prove to be the key (along with a Comp solid-roller camshaft) to making killer power with our modern-day Boss bullet.
Horse Sense: Attention new readers-and those of you longtime readers who may have been ignoring our reports on this project for whatever reason: Things are beginning to heat up now, so we recommend that you read through past issues of 5.0 Mustang & Super Fords (from Mar. '08 to present) to bring yourself up to speed with this radical engine we are working on. Thus far, it's all been about making power with a modern-day, Boss 302-style engine-a stroked 8.2-deck short-block with canted-valve cylinder heads. However, the tables will soon turn toward a Fox-body race chassis and building yet another project car for our steadily growing stable of bad Ponies.
There's no question that we're still excited about the impressive performance of our Boss 340 project engine in its recent debut at Westech Performance Group. If you missed it, the street version of our radical small-block Ford showed and proved on the SuperFlow 902 engine dyno to the tune of 472 peak horsepower and 416 lb-ft of torque at the crankshaft. Version 1.0 was naturally aspirated, built with Ford Racing Performance Parts' Boss 302 engine block, Probe Industries' rotating assembly, Edelbrock's Performer RPM 351C 2V heads, a Comp Cams hydraulic-roller camshaft (0.236-inch intake/0.242-inch exhaust duration at 0.050-inch), a Wilson-modified '69 Boss 302 EFI intake manifold, and Kooks' Fox-body/Boss-style headers.
Probe's engine assembler had our block disassembled prior to our arrival at the shop.
Although the numbers surprised several industry associates who underestimated the engine's potential, we were confident from the project's outset that the Probe Industries-built bullet would be an impressive engine, worth considering for a street-driven '79-'93 'Stang, especially now that the groundwork has been laid for building one. Previously nonexistent parts such as Boss/Cleveland-port-compatible headers and intake manifolds for 302-based engines are now just a phone call and credit card away from companies such as Air Flow Dynamics, Edelbrock, Kooks Custom Headers, and Wilson Manifolds.
We're hoping the changes to our Boss 340 will bring back the past glory of Ford's original Boss 302-a high-winding, high-output, carbureted small-block that ruled the street and road course in the early '70s-by putting our new-school, fuel-injected Boss solidly in the 500hp zone. A shot of Zex nitrous oxide should make it capable of moving the '90 LX it's destined for down the dragstrip in 10 seconds or less.
Despite countless dyno pulls ("Boss Power," Sept. '08, p. 60), the engine's critical hard parts on top and down below all look clean and undamaged.
Our latest procedure, once again performed at Probe by the company's lead engine builder, basically represents another installment in the informal series of 5.0 heads-, cam-, and intake-swap articles that have appeared on these pages over the last three years. Using the unmodified short-block of our first Boss 340, this top-end upgrade involves a trio of harder-core induction and valvetrain components, which we discovered aren't as instantly applicable to a 302 platform as the pieces for Version 1.0.
We gave you the lowdown on these upgrade parts in our overview of all the items we're using to create our Boss engine's split personalities ("True Identity," p. 107, Apr. '08). The parts include Air Flow Dynamics' SP4VS aluminum Cleveland cylinder heads, a Comp Cams solid-roller bumpstick with 0.270-inch-intake/0.274-inch-exhaust duration at 0.050 inch, and Wilson Manifolds' new Boss 302 single-plenum intake manifold with a four-hole, carb-style throttle body
The following photos and captions detail the bolt-on brawn we've added to our Boss 340-parts that we believe will transform it from a hard-hitting street engine to a race-ready bullet with a rev limit that should easily run deep into the 7,000-rpm red zone.