Checking Overall Engine Health

• 1). Analyze the oil. Drain a small sample--usually about 3 ounces is sufficient--and mail it to a testing lab for analysis. Analyzing the engine oil for wear metals and other contaminants can provide valuable insight into the overall condition of the engines internal components. Many labs will provide the necessary test vial (kit) and packaging to send it safely through the mail. An oil test can conclude whether there are metals that indicate abnormal bearing, piston or cylinder wall conditions. For best results, the oil should have at least 1000 miles of use. If results are favorable, the engine's lower end (shortblock) can be used for the remainder of the build. Oil testing can cost around $25.
  
  
• 2). Perform a compression test. A compression test is accomplished by using a compression tester inserted in place of the spark plug and can tell the condition of the upper end of the engine (piston rings, valves and head gaskets). Remove all spark plugs. Disconnect power to the ignition to prevent starting and insert the tester into each cylinder, one at a time. Lock the throttle in the wide-open position and crank the engine over with the starter several revolutions. Record cylinder pressure readings for all cylinders and compare. Some parts stores have compression testers available for rent.
  
  
• 3). Determine if oil analysis and compression tests are favorable and support the continued build. If so, the engine can be modified with performance upgrades. If the results are negative, overhaul/renew the engine assembly with rings, bearings and a valve job. (In many cases, an aftermarket shortblock assembly will be more cost effective.)
  
  

Budget Aftermarket Performance Upgrades

• 1). Replace the intake manifold and carburetor. Factory intake systems are typically designed for standard performance. Aftermarket intake systems can expand upon the factory performance and provide increased output for relatively low expense. Combined with aftermarket headers and an efficient exhaust system, this can be on of the most cost effective upgrades.
  
  
• 2). Install an aftermarket camshaft. The camshaft is responsible for the engine's power characteristics. Factory camshafts are designed for smooth performance and reiablity, but aftermarket camshafts can also improve performance by altering the operating range the power is produced in, depending on the ability of the rest of the intake system and cylinder head capability. Many camshafts (and kits) can be purchased for a few hundred dollars.
  
  
• 3). Upgrade the cylinder heads. This will be the most complex upgrade and likely the most expensive, as well. One popular upgrade is to use GMs 5.7L (350 CID) Vortec cylinder heads. These heads flow better than most other standard performance GM production heads, but require an intake manifold with the Vortec bolt pattern. Alternately, several aftermarket heads are available that support increased airflow and power output.