Complete 408 Stroker Engine Build - The Twister Part 3 - PHR Project Car

For the last few months, we've been assembling the parts to our Fairlane's new 408 stroker. Last month, we put together the short-block with the help of Andy Mitchell of Outlaw Racing ("The Twister: Part 2," November '07) and now we're finishing the assembly and going to the dyno. Along the way, we've learned a ton about small-block Fords, and picked the brains of many Ford builders. Our goal was to power our 3,460-lb '70 Ford Fairlane into the 11s on motor, and for this we needed more than 500 hp. Since we don't build scrap yard junk at PHR, we stuck with the good stuff. The plan was to save where we could, and spend the bucks where they would pay off the most. Except for a few aesthetic touches, we stayed on track.

Last month, the main player was the Eagle rotating assembly that allowed us to punch our 351W up to a robust 408 cubes. This month, the two main stars are the AFR heads and the COMP roller valvetrain. The assembled and ported AFR heads accounted for one quarter of the build cost, but they flow a boatload of air, and that's the key to making good power. They also complement the roller valvetrain with lighter components. Tony Mamo of AFR says: "Including the savings of the lighter 8mm valve, our new 1.270-inch dual-spring assembly is 40 percent lighter than our previous 1.510-inch hydraulic roller. It allows the engine to turn higher rpm than what's typical for a hydraulic roller setup." Working together with these heads is a full roller COMP valvetrain. Ford builders we talked to couldn't stop raving about COMP's Pro Magnum vertical-bar lifters, and how much better they performed over the retro-fit kit (which would need machine work to the block for the retaining spider). Best of all, they just drop right into the lifter bores.

We completed the final engine assembly with the help of Tim Lee at Don Lee Auto, then took the 408 to Westech Performance for some time on the dyno. After a few runs to properly set the rings, and some carb tuning by Steve Brul, the first pulls were made with the dual-plane Edelbrock Performer RPM Air Gap intake and a 750-cfm Holley HP carb, which produced 528 hp at 5,900 rpm, and 527 lb-ft at 4,300 rpm. As expected with the stroker, the torque came on early and hard, with 460 lb-ft way down at 3,000 rpm. Then we switched to a decidedly racier single-plane Victor Jr. intake and 950-cfm Holley HP carb. The 950 is a big carb, but some people thought the engine would easily gobble the extra airflow, and they were right. After a jet change, the 408 roared, and laid down 552 hp at 5,900 rpm, and 530 lb-ft of twist at 4,900 rpm. Clearly, the single-plane will be the right choice for getting down the 1320. The real question is, will it all work together with our other driveline parts to move us down the track in under 12 seconds? We'll know in just a few months, after we install it in the Fairlane, and complete the rest of our safety punch list. Then we'll be heading to the track for a side-by-side duel with the Street Sleeper '68 Chevelle.

Head Games
Heads are the key to big power, so we bolted on a massaged set of AFR 205s. These are based on AFR's popular 165 and 185 heads. As detailed in the first part of this series ("The Twister," October '07), the 205 AFR heads have larger intake ports, raised exhaust ports, and a host of upgrades. Originally we were going to run 185 heads, but Tony Mamo at AFR steered us toward the 205. "The 185 heads would have probably been the best choice for someone more concerned about enhancing the lower part of the power curve where you spend most of the time on the street at part-throttle cruising," Mamo says, "but ultimately the 205s will make more power in the middle of the curve and noticeably more power once the tach starts swinging north of 5,000 rpm." Our mandate was to run in the 11s, so we needed every bit of power we could get.

Tony also persuaded us to do the nitrous-port option, even though nitrous wasn't in our plan. "The nitrous exhaust is simply a stronger-flowing port. 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, on a naturally aspirated engine without sacrificing any peak, or after-peak power. The fact that users can run a tighter spread allows the engine to make more torque and horsepower across the curve. A smaller spread on the valve events also helps to smooth idle and increase streetability. There are numerous benefits from a better flowing exhaust port. For instance, in the event the customer has a boosted or nitrous application, it becomes a no-brainer, as the engine has plenty of intake flow and is in dire need of a better way to exhaust it all."