Smeding's engines use high-silicone bearings with tight clearances to keep control over the moving parts. The Total Seal rings on the Windsor are a low-friction design. The upper ring has a bevel on the inside top edge that gives it a positive twist. The upward tilt of the outside of the ring gives a better combustion seal. The second ring has a chamfered underside that also gives it a negative twist for a better seal against the cylinder wall without increasing friction. Finally, the oil ring they use is an ultra low-friction three-piece stainless steel set. All together, the low oil volume and low-friction rings and bearings give this engine about 20 hp over an engine with looser clearances and standard rings.
The heart of this engine is really in the cylinder heads and the camshaft. When these two parts work in harmony, the most power for the least amount of fuel is produced. Smeding started with AFR's 205cc head, and gave it his own runner and combustion chamber design. They gave these specifications back to AFR, who now produces a special CNC ported head branded by Smeding. They run 2.08/1.60-inch Ferrea valves with 8mm stems. The springs are specific to the hydraulic roller camshaft that's in every 427 Cobra Special. The idea of bigger being better doesn't apply to camshafts. A larger-than-necessary cam may increase high-rpm power, but hurts driveability with a rough, zero-vacuum idle, and poor throttle response. That's why they've chosen a modest COMP grind with 232/240 degrees duration at 0.050-inch lift, 0.565/0.574-inch lift, and a 112-degree lobe separation angle to create usable vacuum at idle and to broaden the powerband. This is a very fast acting cam, meaning that it waits a long time to open, then it opens and closes at a fast rate. This aggressive lobe design can only work with a roller lifter.
The intake is one of the only out-of-the-box parts on this engine, aside from the Scorpion rocker arms. The aluminum Edelbrock Victor Jr. intake also fits the build without modification. Many shops choose to port match the intake to the cylinder head, but that can hurt the torque curve. The step from smaller intake manifold runner to the larger cylinder head runner increases torque, just as stepped headers are well known for.
Finally, the crowning jewel of this engine is a meticulously calibrated Demon carburetor. The engine comes with a 750-cfm Speed Demon, but with our emphasis on racing, we chose to use an 850-cfm Mighty Demon. With the carb and Pertronix ready-to-run distributor, it's time to start the break-in and dyno testing procedure. First they get the engine running, dial in the timing, and basic carburetor settings. They then put a little bit of load on the engine, 5-10 seconds at a time, with increasing resistance each time. They do this about 100 times then start with light power pulls. They look for the right air/fuel ratios before starting the full-power recorded dyno pulls. They generally make three or four pulls, but will continue until the engine produces consistent numbers. This number must meet or exceed those of the crate engine's description. In our case, we got a bonus 6 hp and 4 lb-ft of torque. In addition to the power levels, they simulate light load cruising to check the air/fuel ratio.
If you've decided you must have an engine just like ours, you won't be able to visit them in the Sacramento area anymore because they are moving their equipment and employees to San Antonio. There, they will occupy an 11,800-square-foot shop that dwarfs the establishment they work out of today. No worries though, shipping is still only $200 anywhere in the United States. Smeding's turnaround time is between 3-5 weeks, which is pretty quick when it's made to order. These are built to order and don't sit on the shelves. Each engine comes with a two-year unlimited mile warranty, which is hard to come by these days. Next month, this pup goes into our Mustang project car with a brand-new Keisler five-speed transmission to let us stretch this Windsor's legs.
Ben Smeding specially designed...
Ben Smeding specially designed the ports and combustion chambers on these heads to work on their 427 Cobra Special. To be more cost effective and consistent, he worked closely with AFR to draw out the changes and cut them with a CNC machine. In front of these Smeding-branded heads are a set of Ferrea 2.08-/1.60-inch valves and dual valvesprings matched to the hydraulic roller lifters that will control them.
Here, the Canton pickup specific...
Here, the Canton pickup specific to the road race pan used gets bolted to the standard-volume Melling oil pump. Smeding doesn't like to use high-volume pumps because they send too much oil into the engine that causes turbulence as it makes its way down past the rods into the oil pan.
You can really see the work...
You can really see the work that has been put into this head on the CNC machine. The shape and texture of the runners and combustion chamber were designed specifically for this engine. This is not your off-the-shelf cylinder head.