408-Inch Ford Stroker

The key to any stroker motor is in the crank. Ford 351 Windsors came with a 3.50-inch stroke, whereas the Probe steel unit shown here features a massive 4.00-inch stroke. The longer the “arm,” the more big-block–like bottom-end torque.

Ray Baird of CHP says that if you’re running a 351 block (’81 and older) with a two-piece rear-main seal and using a newer forged steel crank, make sure that the thrust ridge (arrow A) doesn’t hit the block (arrow B) when trial fitting it. The overall diameter of the later-style forged crank’s counterweights are larger and designed for the later one-piece rear-main-seal blocks. If the ridge is anywhere near the block, be sure to clearance it.

While Windsor blocks are pretty stout, for added insurance Baird went ahead and installed a laser-cut Probe main-stud girdle to ensure that the main caps won’t dance around at high rpm. Before securing the girdle, be sure to trial fit it with the supplied washers between the girdle and the main saddle. Since every block is slightly different, the tops of the main caps may need to be shaved with a bench grinder in order to seat the girdle properly.

Again, it’s important to check tolerances. Make sure the oil pump sits flat (arrow A) on the base of the block, and note that the stud next to the oil pump (arrow B) is recessed and is the only one that doesn’t require a washer. Also keep in mind that it may be necessary to modify the stud should it touch the pump. It did in our case, so Baird used a mill (a bench grinder will work too) to shave off the top of the stud to get the needed clearance.

It’s common for a stroker motor to require clearancing at the base of the cylinder walls to clear the rod and rod bolts. The easiest way to do this is to farm it out to a machine shop, but it can be done at home with a die grinder if you are careful.

A burly stroker motor needs a burly cam. Baird is shown here installing a Crane Cams hydraulic roller with 236/248 duration at 0.050 and 0.574-/0.595-inch intake/ exhaust lift on a 112-degree lobe displacement angle.

An essential component for making big horsepower and torque numbers are the cylinder heads. Edelbrock’s Victor Jr. heads feature 60cc chambers, 2.05-inch intake and 1.60-inch exhaust valves, and a healthy Stage 3 massaging from CHP. See how they flow (right).

The Probe CNC- machined 4340 Steel I-beams are about 50 grams lighter than most other H-beam designs. These feature a 6.200-inch length, 2.100-inch journals, and 0.927-inch wristpins.

Probe’s diamond-cut forged 10:1 compression pistons are extremely light, feature a 0.140-inch dish, and a flat wristpin boss. Full skirts and truss rings help maintain the piston shape under severe loads.

Since we were using a non-roller–style block and planned to use a hydraulic-roller cam, we chose Crane Cams, retrofit hydraulic-roller lifters. This drop-in solution provides an easy way to retrofit without any additional machining.

Probe’s extruded aluminum 1.6:1 roller rockers were utilized on top of the Edelbrock Victor Jr. cylinder heads.

We also opted for Probe’s rocker-arm stud girdle made of 6061-T6 aluminum to help further stabilize the valvetrain tango. Priced at only $129.99, it’s an economical good idea.

We used a 50-ounce SFI-approved damper from Probe to balance the crank harmonics.

Once we had the stroker bolted onto Westech’s engine dyno, the initial results unveiled a glorious 498 hp and 495 lb-ft. As impressive as it was, we knew there was more power to be coaxed out of it.

After playing with the timing and adding a 1-1/4-inch open spacer from Wilson Manifolds, we found that the 408 liked 30 degrees of total timing, which ultimately netted us 503.5 hp and 499.4 lb-ft. Not bad for a mild street/strip small-block on pump gas.

MSD’s small-diameter Pro-Billet distributor was designed to fit into the tightest of quarters with its reduced cap and base size.

Fuel metering is handled by a Holley 850-cfm double-pumper carb and Edelbrock Victor Jr. manifold.

Massive big-blocks are fetching eye-candy to performance aficionados, producing ungodly amounts torque and horsepower without buzzing to the moon. While its been said that the “only” way to match the vicious power and rumble of the big-block is with another big-block, these days through careful research and parts selection you can build a stroker small-block that is more than capable of making big noise and still awe the natives with its brutal power production. It’s lighter, smaller, and projects more of a sleeper appearance, and that’s all good.

Coast High Performance (CHP) offers an awesome monster 408ci Ford stroker built from its in-house brand Probe Racing Components rotating assembly. Starting with a venerable 351 Windsor block, the standard 3.50-inch crank is replaced with a stronger and longer-armed 4.00-inch steel crank and combined with a 4.030-inch bore, 6.200-inch Probe rods, and Probe’s PRS dish pistons to produce one stout mega-cube small-block. Should you elect to build one with your own block using Probe’s rotating assembly kit, it’s fairly easy to assemble, but there are things that need attention that wouldn’t otherwise be an issue in a standard rebuild. For instance, the block has to be notched at the bottom of every cylinder wall in order to clear both the rods and rod bolts.

For those who are looking for something a little more complete, CHP also offers a choice of either a complete short-block or a ready-to-run long-block that’s already been machined and assembled with all the Probe goodies. So whether you choose only the internal components or a complete motor, you can be sure of one thing—you’re going to get serious big-block power in a small-block package!