Some of my earliest childhood memories are of my father working on cars. For a few years it seemed we always had some other person's vehicle parked in our yard with no engine or transmission, while pop earned a few extra dollars spinning wrenches on those vehicles. As a kid, it was always exciting to play in and around these vehicles. They seemed like sleeping monsters.
That same childlike excitement manifested itself while at Smeding Performance in Rancho Cordova, California. A built-to-the-hilt 383 with a stacked and polished blower and a couple of carbs appeared much like those sleeping giants from my childhood. It doesn't take much of an imagination to look at this engine and hear its throaty roar and listen to the supercharger whine. All this and it comes out of the box ready to run, just like a new pair of sneakers: lace it up and go.
If you have not heard the name before, Smeding Performance builds solid dyno-tuned crate engines ready for nearly all applications. Ben Smeding also custom-built our 717-horsepower 572 engine that went into the Project American Heroes '57 Chevy. Since the theme this month is small-block muscle, we called Smeding Performance and asked if we could follow along on one of its blown and stroked crate engines from the initial build to the dyno test. A few weeks later Super Chevy was up in the Sacramento, California, area working with Smeding and documenting this buildup of a blown brawler in a box.
A balancing act in progress: Before any type of work begins, the entire rotating assembly will be weighed and balanced. The crank is made from high-grade 4340 forged steel, micro-polished and chamfered. The connecting rods are 4340 forged steel and are 5.7 inches from center to center. The pistons are custom-forged for Smeding, made of high-silicone aluminum with a zero deck surface for better combustion, with full floating wrist pins.
When it comes to stroking a small-block, a cam with a, shall we say, large girth can present a problem. The lobe and the top of the connecting rod's journal can come into good thing. Usually this occurs on the 2 and 6 cylinders; Smeding Performance leaves nothing to chance and chamfers each connecting rod.
All rods, pistons, wrist pins, rings, and bearings are weighed, and each weight is written down. Balancing equals power. Here's an interesting fact: A quarter of an ounce just four inches from the center of rotating assembly at 8,000 rpm is equal to 114 pounds; at 4,000 rpm it becomes 28 pounds; at 6,000 rpm it becomes 64 pounds. Weight and balance are everything.
The rods have a larger chamfer on one side. The crank's larger radius makes this necessary for bearing side clearance. Notice that the bearing is also chamfered. A normal small-block bearing wouldn't work in this application and would actually rub on the radius, causing more unwanted self-machining issues.
The valve guides on these cylinder heads are .0015; Smeding opens up each exhaust valve guide to .0020 of an inch. The reason for honing just the exhaust valve guides is because of the temperature (combustion temperatures and exhaust gas temperatures); honing gives the valvestem more room to expand when operating at full temperature. The cylinder heads used here are Edelbrock Performer aluminum straight-plug heads and 2.02- and 1.60-inch stainless steel valves with 64cc and 170cc combustion chambers. All ports have been machined and matched.
Nice bearings! How often has anyone ever uttered that phrase? We're guessing never. But take a look at these 270-degree bearings compared to the typical 180-degree bearings. For blown and stroked motors, the oil galley from the crank to the connecting rod will be lubed a total of 270 degrees of rotation compared to the standard 180 degrees.
Smeding uses a custom-made, custom-ground hydraulic roller cam with .510-inch intake lift at 231 degrees of duration and .522-inch exhaust lift at 236 degrees of duration and a 113-degree lobe center in all his blown engines. All duration numbers are measured at .050-inch valve lift.
Once all the machining is done to make this a performance engine, the bottom half of the block can finally come together. There's nothing special about installing the rotating assembly, so we decided to include this obligatory "crank going into the block" photo.
In the safety of the dyno room's control center, Martin fires and takes several minutes to seat the rings and run the engine through its paces. Then the final pull happens and we get to see what all this meticulous work Smeding puts into each build produces.
We snapped a photo of the screen just after the engine made its pull. Take a close look at the first three columns on the left side of the screen. The far left side is the rpm speed, the second columns on the left side of the screen. The far left side is the rpm speed, the second column is the torqued at any given rpm, and the third from the left is the horsepower. You can see that at just 2,500 rpm the engine is already at 481 lb-ft of torque and hits peak torque at 583 lb-ft @ 4,600 rpm. The horsepower at 2,500 rpm reads 229, then has a steady climb to a peak number of 601 hp at 6,000 rpm. All in all, this is a stoutly built blower in box that should be fun to drive around the town roasting any street machine's hides.