timing a 350 chevy

red350 said:

what is the proper way to time a 350 .

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There are many 'correct' methods used to time an engine. Here are some pointers that will be true for whatever method used for a carbureted engine with a non-computer controlled distributor.

This is not a performance timing instructions and I am not getting into the plus & minus of ported or full vacuum advance. I am also not posting in this reply anything about timing advance curves or carburetor adjusting. This is not what you asked for at this time.

Some tools that will be needed or very helpful are an adjustable timing light or a regular timing light and either a degreed harmonic damper or one that has "timing tape" installed on it. A wrench to tighten/loosen the hold down bolt of the distributor. A flat bladed screw driver to adjust the idle stop screw (not the air/idle screws). A golf 'T' or a #10 machine screw to plug the vacuum advance hose temporarily. A tachometer. A dwell meter if running an older points style distributor. An allen wrench to adjust the dwell on the points (if running a points style distributor).

Most important and often overlooked. Start the engine and allow it to come to 'normal' operating temps. Be sure the choke is fully open. Leave the air cleaner installed.

Shut the engine off and remove the vacuum advance hose from the vacuum advance cannister. Plug the end of the hose. A golf 'T' works well here or a #10 machine screw will also work. Hook up the timing light. Route the wires for it away from the exhaust manifold and any rotating components (fan, belts, etc.) Restart the engine.

With the engine in neutral (if standard shift), or DRIVE if automatic (be sure to set the parking brake, block the drive wheels and have a helper holding the brakes for this if an automatic trans), set the idle RPM to 600-750.

DO NOT REV THE ENGINE UP UNDER THESE CONDITIONS!

Shine the timing light on the harmonic damper and pointer to see what your initial timing is set at and record that number of degrees. Assuming that you have a shop manual for your vehicle, it should list what the factory recommends for the initial timing. If the figure you observed is not what the factory suggests, then loosen the bolt on the distributor hold down clamp just enough so that you can rotate the distributor. With the engine running and the timing light shining on the timing marks, slowly rotate the distributor body to change the timing. Counter clockwise will advance the timing while clockwise will retard the timing. When the number of degrees you want to use are showing with the timing light, re-tighten the bolt that holds the distributor in place.

Shut the engine off. Re-connect the vacuum advance hose. Re-start the engine. With the engine in DRIVE and the brakes fully applied you may have to re-adjust the idle back down to the 600-750 RPM range if you are running full vacuum advance. The idle in PARK will be slightly higher. You want the idle in DRIVE to be below 800 RPM because at that point the built in centrifugal advance will begin to affect the timing.

Just a point of interest here. Factory timing is usually for emissions control rather than for performance. Setting the initial timing and the Total Mechanical timing to higher than factory specs will yield much better overall performance. A search on this site or another post will yield results for that.