Muscle Mustangs & Fast Fords
Four-Valve Engine Build - Heart And Soul, Part 2
We show you the long and short building of a big-cube Four-Valve.
Superfly- Destroyer of Hideous Camaros is near and dear to our hearts. Our once-editor (now editorial director) Jim Campisano has used this project '97 SVT Cobra in nearly all facets of motorsports. Its high-revving N/A Four-Valve has left many shaking their heads in disbelief with its 11-second timeslips and on-track abilitiesùall in street trim.
Sadly, the heart of Campy's Rio Red Snake has grown tired. Countless trips down the dragstrip shifting above 7,500 rpm and sustained high-rpm blasts around some of the most famed road courses in America have taken its toll. To be frank, the Cobra is whipped.
Last month we gave you a little history on Superfly-DOHCùthis month, we're going to talk about the new engine. We've teamed up with Ford Racing Performance Parts (FRPP), Livernois Motorsports, and many other aftermarket giants to build a 4.6L-based Four-Valve that will bring back Superfly's lost power and push the Four-Valve performance limitsùthe way Superfly did in the late '90s.
The foundation of the engine is an FRPP (modular) Boss 5.0 block. The big-bore block gives you 94mm (3.70-inch) bores, which are 3.8mm larger per cylinder than the stock 90.2mm (3.552-inches) bores. Another benefit is its strength. FRPP added 17mm-thick main webbing and four-bolt mains with nodular-iron main caps. The Boss block weighs in at 165 pounds, making it 36-pounds heavier than it's aluminum cousin, but the added displacement and increased strength make the small amount of added weight a non-issue.
Livernois filled the Boss block with its own rotating assembly. The crank is a Livernois 4340 forged-steel piece with a 3.750-inch stroke. It uses Livernois/Manley forged H-beam rods with ARP 2000 rod bolts to connect the crank to the custom Livernois/Diamond pistons. The pistons have coated skirts and crowns, as well as gas ports for better ring seal. The combination of the 3.700-inch bore and 3.750-inch stroke gave us a displacement of 323 ci (5.3 liters).
The short-block was topped with Livernois Stage 2 CNC-ported cylinder heads. The heads are CNC-ported on a five-axis CNC machine, and fitted with custom-ground factory-size intake and exhaust valves (36mm/1.42-inch intake, 29mm/1.14-inch exhaust). Livernois also does a four-angle valve job to finish off the heads. When all is said and done, the heads flow 310 cfm on the intake side and 255 cfm on the exhaust side at 0.500-inch lift. The heads are mated to the Boss block using ARP head studs and Cometic gaskets.
The valves are actuated by custom Livernois camshafts, which are cut by Comp Cams. The shafts measure 0.475-inch lift on both the intake and exhaust side, with a split duration of 238/238 at 0.050-inch lift and a 113.5 LSA. The camshafts use stock followers and lifters to set the valves into motion, and Livernois single-coil valvesprings return the valves to the seated position. The long-block was then topped with an '03 Mach 1 intake manifold.
When we have the engine on the dyno, we'll test the stock intake against a ported version with a variety of intake spacers. Come back next month as we strap our Livernois-built Four-Valve to the engine dyno and hopefully see some big power!