Last year, Lucas Oil’s Tom Bogner and the engine gurus at Dougans Racing Engines out of Riverside, California put together one super-clean big-block Chevy for Bogner’s wild Davis Race Cars Corvette. Using some powerful components such as Pro Filer’s “Hitman” cylinder heads, an aggressive roller cam from COMP cams, and some custom pistons from JE Pistons, Bogner set out to build one serious naturally aspirated strip stormer. Since we love investigating high-powered engine recipes, we wanted to check out some of the parts and pieces that went into this low 8-second powerplant.
An email from Bogner revealed his passion for hot rods, one he’s had since before he could drive, “I have always had some hot rod or race car. My first car in high school was a ’67 Mustang Fastback with a 390,” Bogner said. “I also built another with a Boss 302, both were 4-speeds cars.” In 2000, he obtained a Super Gas license at Frank Hawley’s Driving School, then later (2007) purchased a Super Comp Dragster and got licensed for it as well. Bogner also played with a 1987 IROC for a while before starting the engine build in question, “That IROC was my first track car,” Bogner said. “When I purchased the car it had a small-block and my first pass at Palmdale it ran 13-seconds at 103 mph, sounded killer, yet was way too slow!” Bogner then pulled the motor and installed a 468 big-block and ran Super Chevy events and local street legal events, running the best of 9.93 at 137 mph, while being totally street legal. “I wanted to go faster, so I sold the Camaro to Ray Fields, owner of Dougans Racing Engines who originally built the 468 it has. I then raced in NHRA Super Comp, and found how fun 7-second runs at over 170 mph were, so decided to get the ’57 Davis Roadster and have Dougans put together a 605 big-block for it.” This brings us to the engine build we’re covering in the next few pages. “I really started making progress after great friend Don Ermshar passed away last year in a drag boat accident in Texas. He gave me a Sonny Bryant crank and he wanted to help me with my engine and that motivated me to do it right. I think about him every time I start the car, he was a great racer and friend.”
The Block & Machining
The foundation of this bullet started with Dart’s Big M engine block. Dart offers the Big M in bore sizes that measure, 4.250,” 4.500,” and 4.600,” but Bogner opted for the largest version for his build, ending with a final bore size of 4.625.” One of the things that makes the Big M block so strong, is the siamese bore design. No, it doesn’t mean the block is from Siam, the siamese term refers to the how the cylinders are tied together. Instead of having space for water between each cylinder, the bores on each side are solidly cast together [see sidebar] for ultimate strength. The block also features a true priority main oiling system, meaning the oil hits the main bearings before the lifters, which helps keep the crank lubed under the highest of engine rpm. The block uses 300″ tall Gen VI style lifters, however modifications for Gen IV style are also available through Dart. Other features of the Big M block include, scalloped outer water jacket walls to improve coolant flow around the cylinder barrels, two bolt front and rear and four bolt interior ductile iron main caps which have splayed outer bolts for extra strength, lifter valley head stud bosses to increase head gasket seal, and a dual oil pan bolt pattern to fit standard and notched oil pans. Although Dart offers their blocks fully machined for a price, Bogner had Dougans Racing Engines out of Riverside, California bore, hone, and deck the Big M block before assembly.
The Heads & Induction
The heads used on Bogner’s combination are Pro Filer’s Hitman castings. They feature a spread port configuration and are designed with a 12-degree intake valve angle. The small, 60cc combustion chamber and 12-degree valve angle means you can run lighter pistons, promoting better combustion and more power. The intake valves measure 2.400,” while the exhaust valves are 1.88.” The intake ports are available in 415cc or 470 cc sizes, however Bogner opted to have them ported by Larry Morgan racing for ultimate airflow. Bogner revealed that in the right hands, these heads can flow over 500 cfm. The heads were actually designed with the stock block in mind too, as the bore space measures the standard 4.84-inches. To match the heads, this combo is also running The Hitman spread port intake. This manifold design was a joint effort between Pro Filer and Reher Morrison Racing Engines. It’s considered a single plane intake, but it’s almost in between a “normal”single plane and a tunnel ram, because it’s cast with a 1-inch carb spacer above the plenum, making it pretty tall. Pro Filer and Reher Morrison optimized it for engines between 540-632 cu. in. engines, making it perfect for the 605 c.i. “Romper Stomper” in this article.
The Cam & Valvetrain
The camshaft in this engine is a custom mechanical roller from Comp Cams. It features a 50mm journal size, which is thicker than the stock cam core to help eliminate potential flex in the cam. When an engine has super-high valve spring pressures flex in the cam can lead to valve float or worse – broken camshaft. This custom roller also was designed with an LS1 firing order. The gross valve lift on this cam measures .877 on the intake side, and .870 on the exhaust. The duration at .050 is 287 on the intake side, and 302 on the exhaust side, with a lobe separation of 115 [see sidebar]. The rocker arms are T&D’s shaft system and have a1.75 ratio on both the intake and exhaust, while custom Manton pushrods articulate the valves.
Crank & Rods
The fact that Bryant Racing has concentrated on perfecting only crankshafts since 1973 goes to show why a Bryant crank is one of the best you can get. Bogner’s engine features a billet steel Bryant crank with a 4.50” stroke, which results in 605 cubic inches when combined with the Dart block’s 4.425” bore. The connecting rods being used in this combo are Oliver’s billet steel I-beams that measure 6.800.” They feature Oliver’s “Parabolic Beam” design that reduces beam stress and delivers one of the highest strength-to-weight ratio of any connecting rod available. All Oliver rods are precision machined using only premium E4340 aircraft quality steel that is heat treated to produce a consistent grain structure.
Pistons
Gregg JE Pistons was responsible for designing the slugs in this beastly engine. Factoring in the Pro Filer head’s 60cc combustion chamber, block bore size, rod length, and deck height, JE’s Gregg Suyenaga designed some nice, gas ported pistons. Bogner explained, “The 60cc chamber on the Profiler head makes it very easy to obtain high compression ratios, so you’ll notice we have an inverted dome yet still produce over 15:1 compression. It sure makes it easy when installing the NGK spark plugs – no need to index them.” The pistons were also sent to Ben Mens at Roush Competition engines to get a low-friction coating on the skirts.
Oiling System
Lubrication of the “Romper Stomper” was handled by Lucas Oil products. It uses a dry sump oiling system which eliminates any parasitic loss that comes from oil hanging on the crank like it does with wet sump systems and a two-peice oil pan from Charlie Williams out of Lake Elsinore, California holds all the lube. Bogner said, “It sealed up very quickly with the Lucas Break-in oil. I am currently using the Lucas Oil racing only 10W-30 synthetic. Is worth another 8-10 hp over the 20W-50 break-in. I think I would have made close to 1,200 hp”
QUICK SPECS:
Carburetor: Holley HP 1,250 Dominator
Intake Manifold: Pro Filer Hitman Single Plane
Block: Dart Big M Tall Deck 4.625” Bore
Heads: Pro-Filer “Hitman” castings 12-degree ported Larry Morgan Racing flowing over 500 cfm
Head Gaskets: Cometic
Camshaft: Comp Solid Roller 50mm core
Timing Set: Comp Belt drive
Crank: Sonny Bryant 4.50 stroke
Pistons: JE Custom 15:1 inverted dome, coated skirts
Rods: Oliver Billet Steel 6.800”
Ignition: MSD Billet Pro Distributor, 7AL3 Box
Exhaust: Rob McCabe
Oiling System: Dry Sump, Wolfe 5-Stage Pump, Mickey Williams Pan
Machine Work: Dougans Racing Engines, Riverside, California
Bogner’s Ride
Bogner has already been abusing this 605 big-block on the drag strip, and so far he’s been doing well. “My first race with the car in Vegas last year I went five rounds in Bracket 1 and three rounds in the Gambler Race, so it’s been a great start. I have had the car in five races so far with only one first round loss so I am very happy with the car. Shawn Langdon went five rounds at the Vegas NHRA Nationals with the car in Super Gas in his first outing in the car as well. You can see the Corvette at many events and car shows all over the country, and we also use it to test new oil products that we develop. It is nice to be able to run the oils on the dyno and then back it up with running them down the track,” Bogner said. Bogner is very close to the 7-second range with his combo, yet is still using a throttle stop. His best run to date 8.28 at 172 mph with over 1.5 seconds of delay in the throttle stop. The Davis Roadsters are actually designed for S/G 9.90 category, so Bogner is working on a set up now for the Lucas Oil Top Comp class in PSCA. This is a new class for PSCA this year and you need at least an 8.60 to get in. My schedule is busy so not much time for racing this year yet next year I plan on running all the Top Comp events and chasing a Championship in PSCA.”
