A close-up view of the piston...
A close-up view of the piston shows the dish top and the nice ring package. The dish top drops the compression ratio. Compression sits at 8.52:1 when that piston is combined with a 0.040-inch-thick head gasket and a cylinder head using a 70cc combustion chamber. The rings are set down a little lower to help protect them from the exploding fuel and air.
Dyno Testing
Groh doesn't have an in-house dyno, so he loaded up our bullet and headed to Opel Automotive Engineering in Streamwood, Illinois. The facility features a SuperFlow engine dyno. Groh brought along 93-octane pump fuel from a Valero station located around the corner from Opel-it's about the most non-trick fuel you can find. Feeding the gasoline to our engine was a MagnaFuel EFI pump and 11/42-inch feed lines and 31/48-inch return lines. The fuel regulator was a Weldon unit out of Groh's NMRA EFI-Renegade race car. Standard 10W-30 oil was used for both the break-in period and subsequent dyno pulls. NGK 11 spark plugs and Moroso Blue Max spark plug wires delivered the electric charge to the cylinders.
The break-in period consisted of some idling and a steady pull at 2,000 rpm. Once the engine checked out OK, Groh and Opel Automotive Engineering owner, Ted Papuga, made a few easy pulls to 4,000 rpm. Groh checked the valve lash to make sure the valvetrain was in proper working order. He also glanced at the tune he put in the Big Stuff 3 engine-management system. A little fine-tuning of the fuel curve and timing events was needed. With the said adjustments, the engine was fired up and the crew took it to 5,000 rpm where horsepower shot up to 833. Groh noticed the boost gauge was fluttering a bit and checked the blower belt. Sure enough, it needed to be cranked down some more as the belt stretched.
Groh selected a hydraulic...
Groh selected a hydraulic roller camshaft for this engine. His many years of experience in racing and engine building has helped him form a vast knowledge of camshafts-especially the hydraulic roller kind. This stick bumps the intake valves open 0.570 inch, while the exhaust valves relieve the pressure by coming 0.575 inch off the seat. Groh credits the 115 degrees of overlap and the special cam lobes as being the key to the smooth idle and nice street manners of this engine.
A tightened blower belt brought a smooth boost curve, and the result was 850 hp and 893 lb-ft of torque at 5,000 rpm. The fuel pressure held steady at 43.5 psi at idle and was advanced at a 1:1 ratio of boost to fuel pressure when at WOT. Groh stepped up the engine rpm and made a full run to 6,000 rpm. The power results were an outstanding 1,043 hp and a stellar 913 lb-ft of torque. Boost peaked at 20 psi at 6,000 rpm. Groh tried to bring the engine higher on back-up pulls, but the ignition system had a miss in it at the higher rpm, so he called it quits. The engine repeated the 1,043 peak number within a few horsepower on the back-up runs.
If the engine could be brought up to the proposed 6,500-rpm limit, we estimate output to be 1,100 or better. "We were picking up about 20 hp per 100 rpm when we had to kill the pull. Based on that, we would have easily run more than 1,100 hp," Groh says. Timing was set at a modest 17 degrees, well within the safe limits of the 93-octane fuel.
We found it interesting that torque kept climbing, and we still hadn't reached a peak number at 6,000 rpm. The long curve is no doubt attributed to the long-stroke crankshaft, which creates a lot of torque. The upward-moving boost pressure also helped the ever-increasing torque figure. This type of torque will have your eyeballs planted in the back of your head when your Mustang is flying down the quarter-mile. The car will feel as if it will continue to pull hard no matter how long you stay in the throttle.
Attaining such ludicrous numbers is signifi-cant because it was only in the early '90s that a small-block Ford engine eclipsed the 1,000hp barrier. Legendary Pro 5.0 racer Gene Deputy had fastened a pair of turbochargers to his 5.0L engine and let it rip with nearly 30 psi of boost. It was a full-on racing engine with custom parts. The final dyno numbers were 998 hp-the kind of results that had people believing Deputy sold his soul to the devil. People were dumbfounded that a small-block Ford engine was on the brink of 1,000 hp. Fifteen years later, we laugh at that notion as our 445ci street engine achieved those power levels with off-the-shelf parts and a 93-octane pump fuel. This hobby has come a long way.
We selected a pair of CNC-ported...
We selected a pair of CNC-ported 225cc TFS Street Heat cylinder heads. The intake valves check in at 2.08 inches and the exhaust valves are 1.60 inches. The heads flowed a maximum of 330 cfm and 251 cfm at 0.750-inch lift.
The Edelbrock Super Victor...
The Edelbrock Super Victor intake manifold bolted nicely to the engine. The runners lined up almost perfectly with the Street Heat intake ports. The manifold came ready for EFI, including the fuel rails.
The fuel rails mount securely...
The fuel rails mount securely on the manifold, and we selected FAST 83-pound fuel injectors. Originally, we thought these injectors were large enough, but we underestimated the horsepower. The 83-pound injectors were on the edge, and Groh spiked the fuel pressure so they could keep up with the fuel demands. In hindsight, we should have just gone with 160-pound fuel injectors to have a safety margin.
A Meziere water pump was used...
A Meziere water pump was used to circulate water through the engine. Keeping it cool is important, especially with a supercharger onboard. We've used these water pumps on several different projects over the years, and each time they worked flawlessly.
This cast-aluminum elbow from...
This cast-aluminum elbow from Wilson Manifolds enables us to mount the Wilson 90mm throttle body. The elbow has provisions for vacuum lines and sensors so you can easily hook up your engine management system, whether it's factory or aftermarket.
The Vortech blower was mocked...
The Vortech blower was mocked up on the engine at the shop. Here, Groh proudly poses with the Superstar Stroker. Moments later, the engine was loaded up and dropped off at Behind Bars Race Cars.