"Chevrolet's crate motors are the baseline for all the sanctioning bodies and racetracks," Kershaw says, "so we knew we needed to match those power numbers if we were going to be accepted. That made our goal when designing this engine right at 410 horsepower, which is something we can achieve very easily with an engine this size. So once we hit that power goal we began experimenting with different camshafts to achieve the absolutely flattest horsepower and torque curves possible. I don't want to tip our hand too much, but we've had very good results. This motor makes close to the horsepower goal across a very wide rpm range, which makes it very driveable and will make power all over the racetrack."
To find more for ourselves, we got our hands on one of the first production models ready for service and immediately tore it down to its component pieces. There will be at least one component change-and possibly more-by the time you read this, and overall, we are pleased with the quality throughout. Kershaw says the engines are assembled at a facility in Texas that is dedicated to Ford's performance engines. They are not individually dyno'd, but each Z351SR is cranked and run on a test stand after assembly for approximately 20 minutes to make sure there are no mechanical problems, oil leaks, or other warning signs. We haven't had a chance to dyno this new motor yet, but what we've found so far is pretty interesting. Check out what we found when we took it apart.
| THE SPEC SHEET |
| Engine: | Z351SR sealed racing crate motor |
| Displacement: | 351 ci |
| Bore: | 4.0" |
| Stroke: | 3.5" |
| Deck Height: | 9.500" |
| Horsepower: | 415 |
| Cylinder Heads: | Z304 Aluminum |
| Valves: | Steel 2.02" interior/1.60" exterior |
| Ports: | 204 cc interior/85 cc as-cast |
| Combustion Chambers: | 63 cc CNC |
| Rocker Studs: | Screw-in |
| Rocker Arms: | 1.65:1 aluminum full roller |
| Pushrods: | 7.850" length, 51/416" diameter, 0.080" wall |
| Camshaft: | Hydraulic roller |
| Duration: | 226 interior/228 exterior |
| Lobe Lift: | 0.498 interior/0.510 exterior |
| Valvesprings: | Beehive |
| Retainers: | Steel |
| Crank: | Forged steel |
| Main Journals: | 3.00" |
| Connecting Rods: | 5.956" length, forged steel |
| Rod Journals: | 2.310" |
| Pistons: | Forged flat-top w/coated skirts |
| Intake: | Aluminum high-rise, single-plane |
| Distributor: | None |
| Oiling: | Wet sump |
| Oil Pan: | Rear sump w/kickouts and windage tray |
 The cylinder heads are Ford's...  The cylinder heads are Ford's highly efficient "Z" heads. They are already popular with hot rodders and should work well here. They feature angled plugs, 63cc CNC-cut combustion chambers, and relatively small ports that still flow well for good throttle response on the racetrack. Valves are steel, and the standard size for stock car racing is 2.020 inches for the intake and 1.600 for the exhaust. Since no modifications are allowed to sealed motors, the CNC-cut chambers are a nice touch. They should help ensure consistent power from one engine to the next. |  Each engine is run on a test...  Each engine is run on a test stand before leaving the factory, but since no fuel pump is included with the package, we doubt one is bolted up for the test run. During our teardown, we noticed that the fuel pump drive eccentric attached to the front of the timing set appeared to be dry. This isn't really a problem. Just use plenty of assembly lube on the fuel pump's lever when you install one. |  The large-capacity oil pan...  The large-capacity oil pan is fully gated and uses a windage "strip" to guide oil into the sump. |
 Although there is nothing...  Although there is nothing you can do about it in a sealed engine, this may be something to keep an eye on. The camshaft appears to be hardened billet steel while the camshaft thrust plate is standard Ford-issue cast. Normally, these thrust plates are matched with a cast camshaft, which doesn't cause wear issues, but a billet steel cam can eat through these plates relatively quickly. This isn't necessarily a red flag, but it will be interesting to see how well these hold up. |  The cam is ground by Crane...  The cam is ground by Crane and features durations of 226/228 and lobe lifts of 0.498 and 0.510 on the intakes and exhausts. |  Engine oiling is standard...  Engine oiling is standard wet sump. We checked the pickup, and it seems well-matched on our engine. |
 The main caps are cast and...  The main caps are cast and use two bolts. With only 410 peak horsepower, it should be more than strong enough. |  The flat-top pistons are forgings...  The flat-top pistons are forgings from Mahle. They have a good, modern design with small slipper skirts and narrow wristpins to minimize weight. The skirts have also been treated to Mahle's proprietary anti-friction coating. The pins are 2.280 inches long with a diameter of 0.927 inch. They are fully floating, and wire locks hold them in position instead of spiral locks, which can cause damage to the piston if the engine experiences detonation. |  The crank is sourced from...  The crank is sourced from Eagle along with the connecting rods. Although both use all the standard Ford dimensions, they are forged pieces that should hold up well to the rigors of racing. |
 The single-plane, high-rise...  The single-plane, high-rise manifold will obviously flow well. The large air gap between the runners and the valley cover should help insulate the incoming air/fuel charge from the engine's heat. | | |