Muscle Mustangs & Fast FordsHow To Engine
Supercharged 427 Windsor Vs. ZEX 557 A460 Stroker - Goliath's Revenge
We Pit A Blown 427-Inch Windsor Against A Juice-Gulping 557-Inch Big-Block.
With maximum power production in mind, we selected a titan-sized camshaft. Comp Cams supplied one of its drag-race roller profiles that offered 0.806 intake lift, 0.763 exhaust lift, and a whopping 275/284 degree duration split (at 0.050). The sizable lift and duration specs were combined with a 110-degree LSA. To work with the healthy cam, Comp supplied solid-roller lifters (PN 836-16) and a matching double-roller timing chain.
Comp also supplied a set of pushrods (actually, two sets of eight) as the intake and exhaust required different lengths. The intakes required 9.20-inch pushrods, while the exhausts were slightly smaller at 8.90 inches. The final component from Comp Cams was a set of 1.70-ratio roller rockers. Ford fanatics may wonder why we chose 1.7:1 rather that the BBF standard ratio of 1.73:1, but the answer is easy. We originally tried a set of BBF Hi-Tech Stainless rockers (PN 1130-16), but they were a tad long from the pivot point to the center of the roller tip. The Trick Flow heads (and Pro Comp heads run on a similar motor) worked best with the 1.7:1 ratio set originally designed for the BBC (PN 1120-16).
Goliath also required a serious set of lungs, so we went for aluminum Power Port A460 race heads from Trick Flow Specialties. TFS offers the Power Port A460 heads in Fast-as-Cast configuration, but we elected to take the flow rate to the next level by stepping up to the CNC-ported version. Flowing 412 cfm at 0.800 lift, the Fast-as-Cast Power Port A460 versions could be hardly be considered a slouch.
The CNC porting transformed the already impressive heads into phenomenal performers. The porting improved the peak intake flow to 465 cfm (at 0.800 lift), with a corresponding exhaust flow of 330 cfm. Every bit as important as the big peak numbers was the fact that the porting improved the flow rate of the A460 heads through the entire lift range. These amazing flow numbers came with an increase in intake port volume of just 20 cc over the as-cast heads (340 cc versus 360 cc). Big flow gains are one thing, but when they come with a minimal change in port volume, you know you have the makings of a winner. In addition to the porting, the A460 heads also featured a stainless 2.30/1.88-inch valve package, 83cc combustion chambers (for a 12.5:1 compression), and a complete valve spring package, including titanium retainers that support up to 0.850 lift. In short, the Trick Flow CNC-ported Power Port A460s were some serious headgear.
Massive displacement, aggressive cam timing and hellacious head flow are all well and good, but they are meaningless if you strangle them with a stock four-barrel intake. Lucky for us, TFS recognized this fact and designed not one, but two different intake manifolds dedicated to the A460 port configuration.
First up was the single-plane R-series A460 intake manifold designed for use with a Holley Dominator carburetor. This intake features high-flowing, extended runners, a raised plenum floor and additional material for custom port work. The R-series intake also features dedicated bosses for direct-port nitrous or fuel injection. TFS also offers an R-series A460 tunnel ram designed to accept either a single or dual Dominator carbs. Naturally, we opted for the dual-carb top and proceeded to call Holley for a pair of new 1,050-cfm Ultra Dominators.
Like the R-series single-plane intake, the Trick Flow tunnel ram was designed for large-displacement, high-rpm Ford motors, and included bosses for nitrous and/or fuel injection. As much as we like a good fuelie motor, there is something wildly impressive about a big-block Ford sporting a tunnel ram and a pair of shiny new Ultra Dominator carbs.