There's nothing quite as exciting or nerve racking as building a new engine. It's exciting because more power is fun, but it's hard on the nerves because it's an expensive investment. Our '70 Fairlane 500, named project Fastlane 500, has been coming along nicely, and we're at the stage where the big Ford needs some big power. When we purchased the Ford, we ran it at the track and knocked down a leisurely 17.64 at 77 mph in the quarter-mile. With a crappy time like that, making it go faster should be easy. Actually, we want the car to be a lot faster, and for that we needed more than what the old 302 could muster.
This kit from Eagle Specialty Products makes a 351W-based 408 stroker a breeze. You get the whole rotating assembly (PN 16123030) in one package for $1,279.95.
We had a lot of choices for a new mill. We could stroke the 302 to a 347, but the larger Fairlane needed torque-generating displacement. We considered going with a 460 big-block, but the swap wouldn't have been easy. We finally decided to stroke a 351W. The question was how big. We called Scott Johnston of Reincarnation High Performance to get his take on our build. He placed third in last year's Engine Masters Challenge with a Ford, so he obviously knows his stuff. He helped us develop our build, and made several suggestions about what would work.
It's All About Cubes
The maximum size that can be made from a 351W is 429 ci, but living near the limit doesn't bode well for longevity. We decided that going with a more conservative displacement would still make great power, and be rock-solid reliable. The choice to go with a 408 over something like a 392 was based on wanting just a few more cubic inches of small-block goodness. Also, the guys on Fordmuscle.com and Stangnet.com have had great luck with 408s, and offered good advice. The Fastlane Fairlane tips the scale at 3,460 lbs without the driver, and the 408 should provide enough torque to overcome that pesky first law of motion.
Also included in Eagle's 408 stroker kit are rod and main bearings, a moly ring set (4.030 bore), and appropriate pins for the pistons. This beats hunting around for all these parts separately.
The Cost
When planning the build, we had to consider cost. We wanted quality, but not at a crazy price. Still, it's amazing how fast this stuff adds up. At first, we were going to run hypereutectic pistons and stock rods with our cast crank, but the cost difference was only about $170 for forged pistons and rods, so we splurged to gain extra durability. We were tempted to upgrade to a forged crank for another $335, but decided to draw the line somewhere, and the Eagle cast crank should hold up to our projected power level easily. We'll have a complete parts list and price breakdown next month when we assemble the 408. Here are the main power players in our 408 engine build.
Forged PistonsOur kit includes .030-over forged aluminum dished pistons. They feature a plasmamoly ring facing and have a .190-inch dish. For many applications, a hypereutectic piston would be fine because they take abuse well and have a favorable expansion rate. These forged slugs are stronger in case we want to experiment with a little nitrous later on. When it comes to durability, forged pistons can't be beat. | 
Eagle has long been known for its quality connecting rods and these forged 6.250-inch 5140 SIR I-beam units are no exception. They're bushed to work with full-floating piston pins. These rods also use ARP 8740 capscrews and have alignment sleeves for easier assembly. They come packaged in weight-matched sets (+/- 2g). |
Eagle can balance your rotating assembly on its Hines equipment. This can save you the hassle of having it done locally, and lets you get right to the assembly. On external balance assemblies, Eagle likes to supply the parts they are balanced with, so they sent us a flywheel and OEM-style balancer. If we choose to run different units like an SFI-certified part, we can have the new ones match balanced to keep the balance spot on. Balancing runs an additional $333, and includes an OE-style damper and flexplate. | |
Stroker CrankThe key player in any stroker build is the crank. A normal 351W has a 3.50-inch stroke, but our crank has a torque-building 4-inch stroke. According to Eagle, its ESP cast-steel cranks have a higher ductility than OE units, and feature .092-inch radii on all journals for extra strength. They also can use OE-style bearings. Brian Taube of Eagle Specialty Products told us that this package is rated for 500 hp at 6,500 rpm. Our mill should make peak power around 6,000 rpm, so we're good to go. "Cast crankshafts are fine for most street/strip applications," Brian says. "Things like heavy pistons and rods, and extreme rpm usage are what cast crankshafts cannot handle. The lighter the piston and rod combo, the better, and extreme rpm can cause a level of harmonics that no casting can handle. For this reason, Eagle builds lightweight connecting rods and uses quality aftermarket pistons to form an assembly for years of reliability."