How to Add Horsepower to a 289 Engine
- 1). Decide on a budget. There's an old saying in racing that applies here: "Speed costs. How fast do you want to go?" The amount of money spent on an engine is directly related to how much horsepower it creates. At least ten thousand dollars will be required to turn an all-original 289 into a race-ready engine.
- 2). Assemble a parts list. The parts list should be as comprehensive as possible, taking into account that things do come up unexpectedly. The major parts that should be replaced are; the rotating assembly (including the crankshaft, connecting rods, and pistons), camshaft, cylinder heads and valvetrain, exhaust headers, ignition system, carburetor, and charged air induction system (supercharger).
- 3). Disassemble the engine in its entirety. The engine block must be tested for structural integrity. You'll also have to take the engine through an extensive modification process which will require that all factory parts and internal components be removed.
- 4). Perform magnaflux and sonic testing. These tests will determine if there are any cracks or weak spots in the engine block and must be performed by a fully equipped race shop. After the engine block has been tested, a number of machining operations must be performed to ensure proper part fitment and smooth operation. Necessary machining operations include: line boring the crankshaft and camshaft journals, align honing the cylinder walls, planing the cylinder deck, deburring and smoothing the oil passages and gallies.
- 5). Install new parts. Not all of the parts mentioned must be upgraded performance parts. Any combination of performance parts will increase engine horsepower. The following is the parts list assembled in Step 2 and approximate horsepower gains associated with each piece: rotating assembly-50, camshaft-100, cylinder heads and valvetrain-100, exhaust headers-25, ignition system-20, carburetor-25, supercharger-200. These are all rough figures, but should provide an idea as to the importance of each piece. All listed parts should be replaced with new ones, even if they are not performance variants.
- 6). Test run the engine. Be sure to follow proper engine break-in procedures. In order to properly break in a new engine, it should be run at various speeds between 500 and 1200 engine rpm's (rotations per minute) for the first half hour of run time.
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