Over the past few years, we have seen massive cubic inch increases thanks to new blocks, heads, and a desire to build the ultimate pump-gas street engine. The trend has always been to build it bigger, as the hot rod clich of "bigger is better" tends to hold a lot of truth in most applications. The build-it-bigger motto has led to massive 800ci and 900ci engines that have eclipsed the 1,400hp range in naturally aspirated trim while running on fossil fuel from the local gas station. As cool and exciting as it can be to own an engine the size of an IHRA Mountain Motor Pro Stocker, it is hardly practical-let alone the fact that it's rather expensive. The extra cubes come in the form of a physically larger package size when compared to the traditional low-deck, big-block platform. Shoehorning these engines into a muscle car almost always necessitates custom fabrication and a hood that requires a periscope to view the landscape to the right.
For most of us, the look and function of a stock or low-rise cowl hood is not only practical, but aesthetically pleasing as well. Scott Shafiroff Racing Engines (SSRE) has the solution to keep the street-sleeper look of your car while increasing the cubic inches to nearly 600. The company offers a line of pump-gas engines to fill any of your needs and we scoped out a 598ci mill that is based on a low-deck (9.8-inch) engine block. "Our 598 fits under the hood of most muscle cars like Chevelles and Camaros, to name a few," commented Scott Shafiroff, long-time engine builder and racer. This is the same engine block size that GM uses for its 396, 427, 454, and 502 big-block family. If your GM car was equipped with a big-block from the factory, then this bullet will fit nicely under the hood.
"This is an engine that I have wanted to do for a long time," stated Shafiroff, as he sought a middle-of-the-road engine package that fit between the 632ci crate engine line and the smaller 540ci offerings from his Ultra Street division. It retails for $12,000, less carburetor and ignition. That is the base price, and SSRE offers choices, not options-as Shafiroff puts it-to further custom tailor the engine to the owner's needs. The engine we followed from buildup to the dyno test featured a few extra items. This package includes the Hot Hydraulic Roller (HHR) upgrade ($995), SSRE-prepped 950cfm Holley 4150 carburetor ($895), Cometic multi-layer head gaskets ($95), SFI balancer ($150), Eagle 3D rods with L19 bolts ($125), and Calico-coated bearings ($150). That brought total cost to $14,410, but output also increased from the standard 775 hp up to 795 hp. This was accomplished on pump gas. Breezing through the menu for this engine, Shafiroff also offers versions for E85 ($295), Extended Cruising (lower compression, new/milder hydraulic roller design, $595), and Saturday Night Special (aggressive solid-roller cam, fully ported heads, 855 hp, $1,895). The menu allows customers to choose and customize the build to their desires, but keep the engine within the SSRE code of production efficiency.
"Production Precision is the process I have developed to keep costs down for the customer, and deliver a quality product," commented Shafiroff. The advantage the shop uses to keep engines moving out the door in a timely manner is a limited menu of choices and a highly efficient shop process. The process allows the company to control inventory so all parts are on the shelf and ready to build at a moment's notice. SSRE's inventory isn't just a bunch of boxes sitting in a warehouse, either. For example, the engine blocks arrive at the shop and the team preps each block in a similar manner-no matter the combination. Each unit is inspected and quality controlled, then put through the machining process using state-of-the-art automated machines. The blocks are stocked and ready to be built before an order is even made. As Shafiroff puts it: "our process is done better and faster due to our automated machinery, which saves the customer money while ensuring a superior product. It's a win-win." These labor savings and the buying power of SSRE ensures the customer gets the best parts at the right price.
Volume sometimes gives the customer the fear of a missed step, but Shafiroff assured us that every block and part is verified multiple times using the most accurate tools. "All the blocks from Dart come a certain way for us. That way the specs and tolerances are controlled here," Shafiroff says. That includes line hones, lifter bores, and cylinder bores. He was quick to point out the lifter bores. The blocks are ordered from Dart with undersized lifter bores. That way SSRE machinists can fit-hone each lifter bore to the proper dimension for the specific lifters the company uses in this engine. These parts tend to vary in size from brand to brand, and this guarantees they are a perfect fit in SSRE-prepped blocks-saving the engine assembler time and effort on final assembly. Lifters can vary up to a thousandth in diameter, depending on brand and style. Once the block is machined, the staff in the machine department verifies all the specs are accurate. Shafiroff also said the cylinder heads, cranks, rods, and pistons are verified and hand-fitted before assembly. A three-page build sheet is issued to the assembler so the proper engine is built to the customer's specifications. We were also impressed that SSRE runs every engine on the dyno for proper break-in and tuning. The cylinders are checked for leakage and the oil filter is inspected before it is sent off to the shipping department.
The 598ci powerplant is based on a modified Dart low-deck Big M block, built specifically for SSRE. The eight-cylinder bores are enlarged to 4.600 inches. That is combined with an Eagle 4340 crankshaft with a 4.500-inch throw to achieve the advertised 598ci. Eagle 4340 steel rods connect the crank to a set of eight custom Mahle pistons that percolate at 10.75:1 compression. Moving up top, SSRE-prepped Dart Pro 1 345 aluminum heads direct the airflow in and out of the cylinders. SSRE uses 2.300-inch intake valves and 1.880-inch exhaust valves; both are made from stainless steel. The Dart heads are also CNC ported for an increase in power. The valvetrain's superstar is a custom-ground camshaft designed by SSRE, and Shafiroff only raised an eyebrow when we inquired about specs. We did manage to coax the basics out of him: 0.646-inch/0.646-inch of lift and 254/262 degrees of duration with a lobe separation of 114. For those who want a rougher, lumpy idle, SSRE will work with customers' desires-sometimes at the cost of a little driveability. The HHR package also includes upgraded Isky Enduro valvesprings to handle the more-aggressive camshaft. Rounding out the valvetrain are chromoly pushrods and COMP 1.7:1 roller rocker arms.
SSRE tapped the Edelbrock Victor 454 intake manifold to rest atop of the behemoth street engine. The engine does not come with a carburetor, but customers can add a Holley 4150 950 cfm or Holley 4500 1,050 cfm at an additional cost. Shafiroff told us that the 950 cfm was a better choice than the Dominator. "If a guy only wants the best performance at the track, then the Dominator is the way to go. But the 4150-style carburetor has better tip-in throttle, and drives a lot nicer," commented Shafiroff. Our test engine was equipped with the SSRE 950 carb, which is a 4150-style piece. If either the Dominator or 950 is ordered, SSRE will set it up on the dyno for proper jetting, and the carb kit also includes AN fittings, studs, gaskets, and a carb spacer. On the bottom side of the engine, a custom Moroso oil pan-with special baffles-is used with a Moroso oil pump inside to keep the bullet well lubricated. A variety of pans are offered for proper fitment in your vehicle; SSRE does not just put a generic pan on the block.
On the dyno, the 598 purred like a kitten, but once the throttle was cracked, it roared to a 6,000-rpm redline. The timing was locked in at 34 degrees and the dyno fuel was Sunoco 93 octane. The dyno mule pushed out 795 hp at 6,000 rpm with a maximum torque output of 768 lb-ft at 4,800 rpm. A Dominator would have upped the power by 25 hp. And if that isn't enough, SSRE offers an optional Speedtech fogger nitrous system to boost output over 1,000 hp on pump gas. All this costs considerably less than a custom 900ci engine, and it still fits under the hood of your muscle car.
BY THE NUMBERS