Here's why:
* Camshaft: Different camshafts have vastly different profiles (duration, lift, lobe separation). A mild street cam might produce significantly less horsepower than a radical race cam. The camshaft is arguably the single biggest factor influencing power output.
* Headers: Header design (length, tube diameter, collector design) affects exhaust scavenging efficiency and thus horsepower.
* Pistons: The compression ratio significantly impacts power. Higher compression generally means more power, but also requires higher-octane fuel. The piston design itself (flat top, dome, dish) also plays a role.
* Edelbrock Intake and Carb: Edelbrock makes various intakes and carburetors with different designs and performance characteristics. A Performer RPM intake will deliver different results than a Performer intake, for instance. The carburetor's CFM rating is also crucial.
Rough Estimate Range:
Considering a reasonably well-built 383 with those modifications, you could expect anywhere from 300 to 450 horsepower at the flywheel. This is a very wide range. The lower end would be closer to a mild street setup, while the higher end would represent a more aggressively built engine possibly with some head work.
To get a more accurate estimate, you would need to provide the specifications of each component (e.g., camshaft part number, header brand and model, piston compression ratio, intake manifold model, carburetor CFM rating). Even then, a dyno test would be the only way to get a truly precise horsepower figure.
