First find the spout plug, it will be near the TFI module. Loosen the distributor lock bolt, start the motor and let it settle down into a stable idle. Connect the timing light to the battery and #1 plug wire, pull the spout plug, and point the light at the balancer where the pointer is, you should see the timing marks. If the marks aren't visible shut the motor off and crawl underneath with some sandpaper to clean off the balancer. After wiping it clean rub some chalk over the timing marks and wipe with a dry cloth so the chalk remains in the marks and highlights them. With the motor running and the timing gun set to zero advance the pointer should be on 10deg, if the gun has advance adjustment and you set it to 10 the crank pointer will be at zero. This is the factory seting, but most motors will handle a bit more, 12-13 degrees, which will make the motor a little peppier.
Actually is should improve milage because the motor will generate a little more Tq. If it's advanced too much the motor will become detonation prone, so try a couple degrees and test it out in various conditions listening for pinging. If you hear pinging back the timing off a degree or 2 and call it a day.
Just make sure you unplug the spout connector before you fire it up.
The spout is what basically "activates" your timing advance system.
Here's where it might be, and what exactly they look like.
Do you have a timing light? Have you ever used one before?
Here's what to do:
Follow this process.
*Mark 10 degrees before top dead center on the balancer with a brightly colored paint or marker, I use a silver sharpie.
*Loosen the distributor clamp just loose enough to be able to turn it by hand.
*Place the leads from the timing light onto the battery, and the clamp around the #1 spark plug. (This is the one that goes to the farthest spark plug forward on the passenger side of your engine.)
*Remove the spout connector.
*Then fire it up!
*Now once it's running, take your timing light and pull the trigger while aiming it at the balancer.
You will see the mark you made clear as day if it's brightly colored.
*Lightly twist the distributor back and forth until it's at the 10* BTDC mark!
*Shut the motor down, and tighten the distributor clamp.
*Then fire it back up, rev the engine a time or two, check the timing again, and shut the engine off.
*Plug your spout connector back in and fire it back up.
*Check the timing again and it should be off a bit now, that's the timing advance working for you.
Then it's just tuning it to find the sweet spot!
Like Paul mentioned, 302's respond well to advanced timing.
You can get to around 13* BTDC with a pretty stock motor without pinging.
Good luck and let me know if you need anything else!
Are you asking about pinging sometimes called spark knock or detonation. It sounds like something is loose in your motor, or like rocks bouncing around in there, or even better like a deisel engine only quieter.
Explaining what pinging is would take a while but basically it's the fuel exploding from the compression before the spark lights it. It sounds like a deisel cause thats how deisels work, no spark just compression. But it's bad for your motor. So just listen carefully, it will be quiet so turn off the radio, you'll most likely here it when climbing a hill.
For the most part you want as much timing as you can get without it pinging. The fuel you use matters also, octain ratings are a measure of the fuels resistance to detonation, like pinging, so if you set it for max timing with super it will most likey ping when you put in regular. This also means that if you wish you can tune for super and get better power and milage and it may be worth the extra cost of the fuel.