1970 Ford Fairlane 500 - 408 Windsor - The Twister

AFR Cylinder HeadsIf clothes make the man, then the heads make the engine. These AFR 205cc heads are based on their popular 165cc and 185cc heads, the only difference is that the intake ports are larger and the exhaust ports are raised .125 inch. They also use premium bronze-manganese valve guides for low friction, tighter fit, and durability. On the other end are ductile-iron seats, so any type of fuel can be used. The rocker bosses are extra thick and feature steel thread inserts. The valve spacing and angles are stock, so any popular valvetrain will bolt on, with the exception of rail-type rockers.

The AFR heads come assembled...        read full caption The AFR heads come assembled and ready to bolt on. They feature ARP 7/16-inch rocker studs, titanium retainers, AFR guideplates, and upgraded 8019 springs. "Including the savings of the lighter 8mm valve, our new 1.270 dual spring assembly is 40 percent lighter than our previous 1.510 hydraulic roller package," Tony Mamo of AFR tells PHR. Total cost for the assembled heads is $1,899 per pair plus the cost of the nitrous port work. They weren't ready in time for this story, but we'll be running 1.75-inch long-tube headers from Ford Powertrain Applications. They specialize in headers for Fords, even raised-port applications like the AFR-equipped 408 going in our Fairlane.

Choosing A Block A 351W is...        read full caption Choosing A BlockA 351W is a taller version of the 289/302 block (9.5 inches versus 8.2 inches). This extra height allows for a half-inch longer stroke. This deck height difference makes the 351W wider than the 302 that's currently in the Fairlane, but it's the same depth. This means it will bolt right in, and because our new trans is a Hughes C4, we won't have to mess with the transmission mount or change the length of our driveshaft. The 1974-and-earlier castings are noticeably beefier than the '75-to-present castings, especially in the critical main-webbing area. The difference between a '74 and '75 casting is over 9 lbs of additional iron. We called AAMidwest and ordered a 351W block of early '70s vintage for $250. All it needs is some machine work and a coat of Ford blue paint.

The Bumpstick
When choosing a camshaft, it's important for it to work well with the cylinder head as a combo. Stiff springs with a mild lobe profile will wipe the cam lobe, but springs that are not stiff enough will cause valve float. When we ordered our AFR heads, we gave them our cam specs so they could install suitable springs. We ordered the rest of our gear from COMP to ensure it would work together. Choosing the cam profile was the hardest part. It was tempting to go with a radical stick to nail a big peak number, but we wanted to ensure that the car still had good low- and mid-range power, and that it was fun to drive on the street. After asking for advice around the Internet, and from Scott at Reincarnation, we came up with a 236/240 duration at .050, .555-/.576-inch lift, 110 LSA hydraulic roller camshaft from COMP (PN 35-426-8, $255.95). This should make good power at the track and be a blast to drive around town.

The AFR's 60cc combustion chamber has been milled to 56cc for our application. A .024-inch thick 4cc cut (to 56cc) is all the straight milling that's allowed. A 46cc chamber is possible if you want to go the angle-milling route. You can also see the stainless 2.080-inch intake and 1.600-inch exhaust valves. With our 56cc chamber and a negative 19cc dish piston, we should end up with a 10.9:1 compression ratio (assuming a .040-inch thick head gasket). The heads also have AFR's nitrous port. "The nitrous exhaust is simply a stronger flowing exhaust port," Tony explains. "Its benefits can be realized on any application, especially if properly cammed to take advantage of it. It allows the end user to run a single-pattern cam (or slight forward split) with an N/A engine without sacrificing any peak or after peak power. The fact the customer can run a tighter spread allows the engine to make more torque and horsepower across the lower and middle part of the curve. A smaller spread on the valve events also helps smooth idle and increase the streetability of the package due to less overlap."

Intake Manifold Our intake...        read full caption Intake Manifold Our intake choice came down to either single- or dual-plane. While a single-plane would generate a slightly higher peak horsepower, it would also lose some in the low- and mid-range areas. Since the Fairlane is a street car that will go to the track, rather than the opposite, we opted for a dual-plane Edelbrock Performer RPM Air Gap intake (PN 7581, $239.95). The Air Gap separates the runners from the heat in the valley cover, and helps keep the air/fuel mixture cooler. When we dyno the engine, we might try a single-plane Victor Jr. just to see the difference.	The rest of our roller set-up...        read full caption The rest of our roller set-up consists of COMP High Energy hydraulic roller lifters (PN 851-16, $245.95) and COMP 1.6 ratio roller rockers (PN 1044-16, $348.39). Roller systems yield big benefits in performance due to less friction. This allows for more aggressive ramp rates and higher lift without sacrificing driveability. Not shown is the COMP retro-fit kit (PN 31-1000, $53.99) that allows us to install these roller parts in our pre-roller block.	The Carb Contributing Editor...        read full caption The Carb Contributing Editor Steve Dulcich likes big carbs, and thinks that if tuned correctly, this Holley 950 HP (PN 80496, $709.95) will work great on our 408. Scott at Reincarnation agrees. Others tend to think it's too much carb. To settle the debate, we will dyno our 408 with this 950 and a smaller 750. May the best combo win!
Dyno Simulation We plugged...        read full caption Dyno SimulationWe plugged all of our data into our DynoSim software, including the flow numbers provided by AFR, and got a peak of 512 hp at 6,000 rpm and 522 lb-ft of torque at 4,000 rpm. This was with a conservative ramp rate for the camshaft and with the muffler option turned on. Once we get the engine assembled and on the engine dyno, we can see how close this prediction is.