* Points Ignition: A points-type ignition system will require a dwell adjustment. The typical range for a points-type distributor in a 1971 350 is between 28 and 32 degrees. However, you must consult your owner's manual or a reputable service manual specific to your engine and distributor to find the precise specification. Attempting to find the dwell by trial and error can damage the points.
* Electronic Ignition: If your 1971 350 has an electronic ignition system (HEI, for example, which became increasingly common in later years but *could* have been factory or aftermarket in '71), then there is typically no user-adjustable dwell. The dwell is controlled electronically within the ignition module.
How to find the correct dwell:
1. Identify your ignition system: Look at your distributor. Points-type distributors have a pair of points inside, while electronic ones will not.
2. Consult a service manual: A Haynes, Chilton, or factory service manual for your specific year and model Chevrolet 350 will give you the precise dwell specification for your ignition system. This is the most reliable source.
3. Use a dwell meter: If you're adjusting points, you'll need a dwell meter to accurately measure the dwell angle.
In short, don't rely on a generic answer. Find the right service manual for your specific engine. Incorrect dwell can lead to poor engine performance and even damage.
