Sonny Leonard's Take On Big Inches
When asked for a few pertinent comments on big inch engines, Sonny Leonard had this to say: "A naturally aspirated 800-plus cubic-inch Pro Stock engine with our GM-compatible Hemi head is nothing short of a beast. These engines make around 1,750 hp at 7,600 rpm and 1,300 lb-ft of torque at 5,800 rpm. To harness this in a 2,400-pound five-speed Lenco-equipped Pro Stock car, super-low ETs are really a question of dialing in the clutch just right."
"Most drag-race engines for Top Sportsman and other high-end bracket classes have around 1,100 hp without nitrous and often use automatic transmissions. This combination, having less power and a converter to soften gearshift aggression, is far easier to utilize. As you might expect, all-out big-inch engines require more maintenance. The 1,750 hp they deliver doesn't just happen--it comes at a price. The super-high valve lifts and very big valves take their toll on valvesprings. With around 17:1 compression, spark timing and carb jetting is critical. With this type of engine the valvesprings and aluminum rods dictate a rebuild about every 30 quarter-mile passes. Going faster means more maintenance, and that means having a more knowledgeable crew. A 737-inch engine with our GM Hemi heads and two stages of nitrous delivers approximately 2,100 hp. Speed and larger cubes are always going to cost big money, so it's all a question of how fast can you afford to go. An IHRA 815-inch Pro Stock Hemi-headed engine will cost $92,000. However, if that's a little too steep, you can save 20 grand by going with my two-stage nitrous-injected 737-inch Pro Mod unit, as they only cost $72,000."
Scott Shafiroff On Big Engines
When asked for a few pertinent comments on big inch engines, Sonny Leonard had this to say: "A naturally aspirated 800-plus cubic-inch Pro Stock engine with our GM-compatible Hemi head is nothing short of a beast. These engines make around 1,750 hp at 7,600 rpm and 1,300 lb-ft of torque at 5,800 rpm. To harness this in a 2,400-pound five-speed Lenco-equipped Pro Stock car, super-low ETs are really a question of dialing in the clutch just right."
"Most drag-race engines for Top Sportsman and other high-end bracket classes have around 1,100 hp without nitrous and often use automatic transmissions. This combination, having less power and a converter to soften gearshift aggression, is far easier to utilize. As you might expect, all-out big-inch engines require more maintenance. The 1,750 hp they deliver doesn't just happen--it comes at a price. The super-high valve lifts and very big valves take their toll on valvesprings. With around 17:1 compression, spark timing and carb jetting is critical. With this type of engine the valvesprings and aluminum rods dictate a rebuild about every 30 quarter-mile passes. Going faster means more maintenance, and that means having a more knowledgeable crew. A 737-inch engine with our GM Hemi heads and two stages of nitrous delivers approximately 2,100 hp. Speed and larger cubes are always going to cost big money, so it's all a question of how fast can you afford to go. An IHRA 815-inch Pro Stock Hemi-headed engine will cost $92,000. However, if that's a little too steep, you can save 20 grand by going with my two-stage nitrous-injected 737-inch Pro Mod unit, as they only cost $72,000."