For Distributor Ignition (points or electronic ignition module, but *not* HEI):
* Crank: The timing tab on the harmonic balancer should align with the 0° mark on the timing pointer.
* Distributor: The rotor should point to the number one cylinder terminal on the distributor cap. *Crucially*, you must then verify that #1 piston is at Top Dead Center (TDC) on the compression stroke. This means the piston is moving *up* as it reaches TDC. This is often confirmed by checking the valve positions (both intake and exhaust valves should be closed).
For HEI (High Energy Ignition):
The process is similar, but there's often less direct visual confirmation of the distributor's alignment because of the HEI's internal design.
* Crank: The timing tab on the harmonic balancer should align with the 0° mark on the timing pointer.
* Distributor: While there might not be a readily visible mark on the HEI distributor itself, the crank timing mark at 0° is paramount. Proper HEI operation largely depends on the crankshaft position.
Important Considerations for Both:
* Before you start: Disconnect the negative battery terminal to avoid electrical shorts.
* Top Dead Center (TDC): Always verify that #1 piston is at TDC on the compression stroke *after* aligning the timing marks. This is critical. Using only the timing tab and pointer can be inaccurate without this confirmation.
* Initial Timing: The 0° mark is usually the *initial* timing. Your engine's actual timing will likely be adjusted slightly by a mechanic or with a timing light. The factory specification may vary slightly depending on the specific engine options and the emissions equipment fitted to your vehicle. Consult a factory service manual for the precise specification for your engine.
* Service Manual: The best and most accurate information will be in a 1979 Chevrolet 350 small-block service manual specific to your vehicle. This manual will contain the exact specifications and instructions for your engine.
In short: Aligning the timing marks to 0° on the crank is the first step, but verifying #1 piston is at TDC on the compression stroke is absolutely essential to ensure the timing is correct. Consult a shop manual for precise instructions and specifications. Getting this wrong can damage your engine.
