Most of the time, the steps to take to set the timing are on the catalyst sticker under the hood. But first, you must get the vehicle into base timing (usually disconnect a wire from distributor). Remove distributor hold down bolt, hook up timing light to #1 spark plug wire, start engine, and align timing mark (0°) Once this is set, reconnect the wire you had to disconnect for base timing. Timing advance will automatically set itself. if it doesn't, you have a faulty timing advance mechanism on the distributor. You can check timing advance by pointing the timing light at scale (while hooked up to #1 spark plug wire) and rev the motor. Timing marks should move up the scale.
On many GM cars and trucks the wire that you disconnect is solid gray in color, it is in the wiring harness on the firewall, the wire has a black plug for separating when doing the timing.
You need to find someone that has an advance timing light. With it they can set the total advance at 35 degrees at 2,000 RPM. That will be your best performance setting.
5 degrees BTDC. remember to set the idle to 800rpm for automatic transmission and plug the vacuum advance ose before setting the timing.
2/15/08 I don't know when this was posted, but the steps are. 1. disconnect timing connector (which I cannot find). 2. connect timing light to no1 sparkplug. 3. with engine running at idle check for 0 degrees. 4. if not loosing distributor bolt and turn for 0 degrees tighten bolt. 5. reconnect timing connector.
The vacuum canister can advance 24 degrees beyond initial timing.
5 degrees BTDC electronic advance must be disabled first then 5degrees before tdc
Engines 389 and larger can be set for 6 degrees BTDC. Remember to disconnect and plug the vacuum advance hose before setting the base timing.
8 Degrees BTDC. / Before top dead center. Be sure to unhook the vaccum advance on the distributor when setting the timing.
just the top one that is the vacum advance, timing should be 2 degrees BTDC with vacum advance line removed and blocke
I didn't see a specific year year you're interested in, however a 1978 Olds 403 is listed as 18 degrees initial timing (detach and plug vacuum advance hose while setting initial advance).
the timing shoujld be 8 degrees BTDC. If your engine has a vacume advance hose running to the distributor than you will have to remove it from the distributor and seal it off before setting the timing.
10 degrees advance
-6 degrees BTDC