383 SBC Build, Part V: A Prototype Never Produced- Chevrolet’s “Super-Fire V8”
By Ryan Manson * clampdowncomp@gmail.com
Here’s the valve-in-head V8 as only the leader can build it and here are some wonderful things it brings you: 578 horsepower and 620 lb-ft. torque made possible by the employment of an extremely efficient centrifugal supercharger. Exceptionally high horsepower in a brilliant package yields GM’s most potent pound-for-pound power producer to date! Chevrolet’s “Super-Fire V8” delivers phenomenal performance, surprisingly high gas mileage, and extra-long life.
I imagine that’s how the ad would appear if GM built a centrifugally supercharged 283 engine back in the day and I imagine this is how it would have looked as well. I have to admit, it’s pretty cool and I think the numbers speak for themselves. Dressing a modern engine up in vintage clothing is nothing new, but doing so while making serious power is always fun. I’ve built 3×2 combos that look the part but lack in performance, so achieving both is a pretty neat accomplishment.
In the past couple stories, we’ve covered our 383 build from the bottom up. This time, we’re going to wrap things up on the top end, bolting on a TorqStorm centrifugal supercharger.
What happens when you redesign an existing supercharger from the inside out? You end up with a component that is superior in every way. TorqStorm started with a pair of CNC-machined billet aluminum cases, designed to promote efficient bearing control, a problem with similarly configured superchargers in the past. The cases were engineered with a V-band clamp-on scroll for easy adjustment of the blower’s outlet, allowing it to fit a wide range of applications. Hybrid ceramic bearings, designed specifically for the TorqStorm supercharger, tolerate internal speeds upwards of 80,000 rpm. A self-contained oiling system, using proprietary oil, cools and lubricates the internal components, another feature designed specifically for the TorqStorm supercharger. Coupled with the internal gears, which are coated for increased heat control, and the billet impeller, which is machined on a 5-axis CNC machine, the TorqStorm supercharger is capable of handling over 700 horsepower while producing air outlet temps under 200 degrees. That makes it perfect for our application, where the blower is connected directly to the throttle body, without an intercooler or water-meth injection. This keeps the installation simple, affordable, and effective.
In the end, our goal of creating a contemporary power plant with vintage styling has succeeded beyond our imagination. And with dyno numbers that back the impressive performance of a rather simple engine build, anyone with a few hand tools and basic engine building skills can do the same. CC
Following our baseline dyno session last month at Westech, which yielded a modest 409 lb-ft and 364 hp, our engine is broken in and ready for some boost!The TorqStorm centrifugal supercharger features a two-piece billet aluminum housing that attaches to the scroll via V-band clamp, making it a very versatile component. We’re using a 2.85-inch diameter cog pulley, good for upwards of 13 pounds of boost. The key to the TorqStorm recipe for success is this turbocharger-style impeller that the boys machine on a 5-axis CNC machine. Its design allows the relatively small blower to support over 700 horsepower while keeping the air outlet temps under 200 degrees. Mounting of the supercharger is handled by a pair of billet aluminum brackets, machined from ¾-inch stock to eliminate flex, and feature a built-in belt tensioner.TorqStorm provides a finned aluminum carb hat as part of their Vintage Kit that we’ll be using to blow through the MSD Atomic throttle body. It will be plumbed to the supercharger via silicone hoses, mated to a six-inch section of aluminum tubing that houses the TorqStorm blow-off valve. The blow-off valve is attached to a manifold vacuum source and serves to prevent compressor surge, allowing the excess air to vent to the atmosphere when the throttle blades are closed. Another part of TorqStorm’s Vintage Kit is this air cleaner, complete with brass ID tag to further lend to its classic identity, which attaches to the scroll housing on the supercharger.To ensure positive engagement at all times, TorqStorm’s Vintage Kit uses a Gates Poly Chain GT Carbon belt and matching pulleys. Stronger than the more common square tooth Gilmer-style belt setup, the radius tooth design also requires less tension, reducing component stress and wear.Mounting the supercharger is a simple affair consisting of two brackets and a handful of bolts and spacers. First, the head bracket (#ARP-GM10012) is attached to the head using the bottom right hole and corresponding fastener.Next, the supercharger bracket (#ARP-GM10004) is attached using the provided spacers (#ARP-S-75-1675) and hardware. All the fasteners are then torqued to 29 ft-lbs. The supercharger can now be installed using the seven 3/8-inch fasteners. The air filter attaches to the scroll side of the supercharger. We used an offset base (available from TorqStorm) to clear the POL valve covers. Block hugger headers courtesy of Hooker Headers also provide extra clearance where stock exhaust manifolds won’t. Next, the finned aluminum carb hat is attached to the MSD Atomic throttle body. The two piece design allows the base to attach directly to a carburetor or throttle body, while the top attaches to the base using nine #8 fasteners, allowing for removal of the induction system without disturbing the box-to-carb seal. Silicone hoses mate the hat to the supercharger, in addition to a section of aluminum tubing, to which the TorqStorm blow-off valve attaches. An 1/8-inch NPT port for water-meth injection is also fabricated into the tubing, for higher (+8 psi) boost applications. The blow-off valve will be connected to a manifold vacuum source, allowing it to vent excess pressure when the throttle blades are closed. TorqStorm’s cog pulley attaches to any conventional crank hub or damper using the included spacer and hardware and facilitates the use of a two-groove pulley setup. This proved tricky as most power steering bracket kits utilize a third groove pulley arrangement. We solved this by using a thinner rear power steering bracket from Alan Grove Components and by pressing the power steering pulley slightly farther on the pump than normal. This allowed us to use a two-groove pulley on the crank.Here’s the TorqStorm kit, installed and ready to rock.
A Period Performer
To further enhance the “period prototype” aspect of our 383 build, I decided to fabricate a carb hat from a stock ’55 Chevy oil bath air cleaner. This required cutting the entire “oil bath” section away from the lower half and modifying the upper snorkel so that it could easily mate to the 4-inch silicone hose provided in our blower kit.
Here’s the original oil bath internals that will be discarded. The remaining lower half was then trimmed to fit around the MSD throttle body while clearing the Edelbrock intake manifold. Once sufficiently trimmed, a flat plate was fabricated from sheetmetal and tack welded to the lower half. A whole was also cut from the center, corresponding with the throttle body’s diameter. Since the lower half would cover a significant portion of the throttle body, a window for the carb linkage to pass through was also cut in the side.Here’s the lower half in place on the MSD Atomic throttle body.The original snorkel was a flattened oval shape, common on late ‘50s small block engines. This was cut from the air cleaner body and a 4-inch round section of tubing was welded in place and blended into the air cleaner body using body filler. A few hours’ worth of sanding and a couple coats of Eastwood High Build Primer, followed by a half dozen coats of Eastwood Chassis Black and a perfectly placed decal thanks to Classic Industries yields this period-perfect beauty.
The Proof’s In The Pudding
Following an initial test and tune dyno day at Westech to give the MSD Atomic a chance to self-learn, our small block made a respectable 441 lb-ft torque and 395 hp, naturally aspirated. For a 383ci Chevy, this wasn’t by any means ground breaking, but given the relatively low static compression ratio of our build, this wasn’t too surprising. Bolting on the TorqStorm supercharger however, changed things quite a bit, with the torque numbers jumping nearly 200 lb-ft to 620 and the horsepower increasing to 578 with nearly 13 pounds of boost at the top end. For the street, this combo might prove a bit much, but since max torque is happening around 4,600 rpm while making 10 lbs boost, it’s actually quite a streetable combo.
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