Rocco Acerrio of A.R.E. Performance & Machine of Simi Valley, California (www.areperforman
As we noted in the second stanza of this series ("Best of Both Worlds;" Jan, '10, p. 70), the term "racing" is somewhat global, with respect to the ways in which Mustangs are modified for and used in various types of motorsport competition. However, despite Mustangs' versatility-especially those equipped with the pushrod engines-drag racing is arguably recognized as the number one form of competition for daily driven and purpose-built Ponies.
Major differences are easily recognized when comparing hard-core racing cylinder heads to their streetborne siblings. Racing heads feature larger and more-elaborate, CNC-ported combustion chambers, and (exhaust) ports that are considerably raised to give air a smoother, straighter exit from the cylinder. They also feature thicker deck surfaces for flat and angle milling (to increase compression), and some have canted valves, which set them far apart from conventional heads.
While some of the street-and-track heads mentioned earlier can contribute to 1,000 rwhp, the big dogs that are included in this report all are capable of helping a Ford small-block engine produce power that is deep into the quadruple-digits with a power adder. Pricing for race-specific cylinder heads typically starts at $1,100 each-in some cases-for just the bare castings alone.
From a cost perspective, the heads being featured in this story are far beyond the needs and affordability of our core group of readers who own daily driven street 'Stangs. However, in the spirit of "equal time" for all of the categories of usage for which cylinder heads are made, we're closing out our series with the bad dudes that are detailed in the following photos and captions.
Air Flow Research
AFR's 225 cylinder heads (PN 1451; 58cc chamber and PN 1456; 72cc chamber; $2,019), are the next (and final) level in the company's small-block Ford head lineup. They share many traits of the 205s that the 350ci bullet in our '86 T-top coupe uses to generate 866 rear-wheel horses (stay tuned for an upcoming report on reaching that new power plateau). The larger heads are 100-percent CNC-ported and flow gobs (intake flow measures 324 cfm at 0.700-inch lift) of air across 2.08 (intake) and 1.600 (exhaust) valves. The 225s are recommended for 347-to-427 stroker engines that turn as much as 8,500 rpm. One important spec to note is that exhaust ports are seriously raised, to 0.375-inch taller than a factory head, which makes them as race-specific as it gets, in the grand scheme of things.
We bet almost everyone competing in the NMRA's Super Street Outlaw class already knows what Brodix Neal heads are. They're the canted-valve, raw-dog heads found on many Super Street Outlaw and Outlaw 10.5 engines. Yes, those castings make tremendous steam. However, Brodix also offers a little-known fully CNC-ported race castings for the classes that require conventional heads. While we couldn't confirm their NMRA legality, Brodix's Track 1 Fs (PN STS T1 F STD 214/214cc; 68cc chamber; 2.08-inch intake valve/PN STS T1 F STD 225/225cc; 68cc chamber; 2.10-inch intake valve; $2,744.38) appear to be suited for EFI Renegade-type engines. With intake flow of 334 cfm at 700-inch lift (for the 225s) and exhaust ports that are raised 0.500-inch from the factory big-cube, Windsor-based engines that spin to 8 grand are the type of engines that these Track 1s thrive on.
We used images of fully assembled Dart Pro-1 CNC cylinder heads and their bare castings (PN 13072143; 62cc chamber; 2.08-inch intake valve; with 1.550 [OD] double valvesprings, $2,910.70) to lead off our first two stories in this series, and they sit atop a complete Dart 347 long-block that we'll be telling you more about in a future issue. Pro-1 CNCs feature 225cc intake ports (2.150x1.300-inch) that flow 325 cfm at 0.700-inch lift, and equally as large, raised (0.135-inch) exhaust ports that flow 235 cfm.