Engineers sometimes say developing a contemporary muscle-car engine is a challenge like no other.

Everybody – most importantly, the buyer – expects it to be powerful. But how far should you go with refinement? Muscle-car “authenticity” is crucial – particularly for a V-8 powering the latest incarnation of a fabled Detroit ponycar – yet customers will not accept any ’60s-era unruliness today, even in the name of “retro.”

Get the blend right, though, and the result can be special. Ford Motor Co.’s new 4.6L SOHC V-8 is special.

Wide-open throttle brings the V-8 basso-bellow you expect – and want – but Ford engineers wisely knew there should be a limit to the sheer decibel output. There’s none of the “are-the-exhaust-manifolds-falling-off” bawl that shreds the eardrums when demanding full power from GM’s new LS 6L V-8 in the Corvette, for example.

Ford 4.6L SOHC V-8 imparts impressive blend of brawn and sophistication.

It’s not just the sound that’s nearly perfect: Ford’s 4.6L V-8 doesn’t mind if you like the view from the upper end of the tach. Things don’t get grumbly until just a few hundred rpm short of the 6,250-rpm redline. And you can come out punching with prodigious doses of torque at just about any engine speed – precisely what you count on from a true muscle-car.

With the move to a 3-valve configuration – and the ripping 40-hp increase it brings over the previous 2-valve 4.6L – Ford’s modular SOHC V-8/V-10 family gels into one of the industry’s most convincing engine lines, a masterstroke of manufacturing and engineering flexibility for Ford. The cylinder heads, for example, are completely identical for both the 4.6L and 5.4L V-8s.

Each cylinder’s three valves in the 4.6L now are governed by a trick camshaft-rocking mechanism that imparts variable valve timing from the single cam in each cylinder head. And Ford engineers also import from the 5.4L Triton V-8 the unique intake-tract tumble flaps that optimize intake-mixture swirl, which improves torque and cuts emissions.

The 4.6L V-8’s newfound revving ability brings us to one of the few things we’d like to see improved: a little more effort at internal balancing that might help deliver a redline in the import-challenging 7,000-rpm range, combined with a lighter flywheel for a bit more urgency in answering the throttle.

But nobody in the automotive world delivers 300 hp for the Mustang GT’s $24,995 base price, meaning Ford’s stellar 4.6L V-8 is the unqualified performance bargain of 2005. Ford’s painstaking blend of new technology and muscle-engine emotion has evolved the 4.6L into one of the industry’s most exciting small-displacement V-8s.

Ford
4.6L SOHC V-8
Engine type 4.6L SOHC 90° V-8
Displacement (cc) 4,606
Block/head material aluminum/aluminum
Bore x stroke (mm) 90.2 x 90
Horsepower (SAE net) 300 @ 5,750 rpm
Torque 320 lb.-ft. (434 Nm) @ 4,500 rpm
Specific output 65 hp/L
Compression ratio 9.8:1
Application tested Ford Mustang GT
Fuel economy for tested vehicle (EPA city/highway mpg) 17/25

bvisnic@primediabusiness.com