We’ve got the answers—the Summit Racing tech department tackles your automotive-related conundrums. This week, we’re looking at ways to make 400 horsepower from a Chevy 350 engine—and whether it’s the right option for a Blazer 4×4.
Q: I need some advice on putting together a 400-horsepower Chevy 350. The engine will be in a Blazer 4×4 with 35 inch tires. I intend to use the Blazer as a daily driver, so I also need to know what gear to run in the front and rear axles.R.Q.
A: To build a 400-horsepower small block Chevy, here are the basics you’ll need:
- 10:1 compression
- Aftermarket cylinder heads
- Camshaft with 230-degree intake/240-degree exhaust duration at .050-inch lift and .480-inch-.500-inch lift
- Edelbrock Performer RPM intake manifold and 650 cfm Holley double pumper
Getting your engine to 400 horsepower is achievable with this combination, but is certainly not ideal for street use. That’s because the camshaft in this combination is designed to make high-rpm horsepower in a lightweight vehicle. In a heavy vehicle like your Blazer, which will require at least a 4.10 gear in those axles to spin the 35 inch tires, you need a lot of low-end torque to get moving—and that means a cam that makes less high-rpm horsepower. When it comes to gas mileage, you can expect no more than five to eight miles per gallon in this scenario.
Not exactly ideal daily driver material.