Timing for a 318

Get an advance timing light from Sears and map it out from idle to 3000. Then run it over 2000 and set total advance to 34 - 36° advance at 2500 - 3000 rpm with the vacuum advance connected if you are using it. Set it the same 34 - 36 total if you are not using vacuum advance, you will just have more initial timing at idle. Try with the vacuum advance connected and disconnected to see how it runs best.

Also, check the mechanical advance springs in the distributor. I told my dad his Superbird had too much advance after he had it tuned up, but he told me not to touch it. He replaced the distrubutor with a Mallory mechanical one after a while. A couple years later when I was taking apart distributors and putting them back together to learn and practice fixing them, I found that one of his springs had broken on the mechanical advance causing it to get too much advance too soon.

You don't have to take it apart to check it. Just take it out, remove the cap and rotate the shaft looking past the vacuum advance plates to check if they are still good. Then put it back in and set your timing which you have to check anyhow.