What is the timing specs for a chevy 98 suburban V8 350 gas.

The ignition timing is not adjusted with a timing light or with the engine running, and to set the ignition timing follow these proceedures.

There is a mark or notch on the distributor housing that the rotor should be pointing to when the engine is on top dead center. This "static" timing is all that matters and the computer will be able to control the timing as long as the ignition rotor is in that position when the engine is at top dead center.

1. Place the engine at top dead center.

2. Look under the distributor cap and find where the number one terminal runs under the distributor cap, and where that position on the distributor cap corresponds with the distributor housing, and it should match up to a mark or a notch on the distributor housing indicating the number one position.

3. With the engine on top dead center the ignition rotor should be pointing to the number one mark or notch that is on the distributor housing, if it is not then loosen up the distributor and turn the distributor until the ignition rotor is pointing to the mark or notch on the distributor housing and then tighten down the distributor, the engine should now be static timed.

If the distributor can not be turned enough to align the ignition rotor with the number one mark on the distributor housing, or the distributor does not set properly and will not allow the installation of the spark plug wires then the distributor is not installed correctly and is most likely a tooth off and it will need to be re-installed correctly. (The distributor should set like it is shown in the firing order diagram when it is properly installed)

Here is a firing order diagram to also help assist you.