[vettestr]

Timing and more specificlly initial timing is one of my favorite tuning tweeks. As Always the guys who already answered have given great advice. I do most things NXS, try it and see what you think. Engines LOVE timing and more is better until you reach the max of your combination.. I am running 26 degrees initial but other mods also help allow that much timing.
I strive for 15 to 20 degrees initial on most engine combinations but you must also limit total to about 39 /40 max. without vac advance. Adjustable Vac units are available if you want to run it but will take extra tweeking with a high threshold. Knocking or preignition with difficult starting will limit your combo. The hard starting can be eased by stroking pedal 1 or maybe 1.5 times before hitting the key if you are carb'd. Key must be on if injected for enrichment before starting.
Check for pinging by loading when up to normal temp, (at lower rpm put in say 3rd gear at low speed and try to accelerate) listen for pinging. Advance to max until pinging and then retard 2 or 3 degrees from that point as rule of thumb. Be sure to check and limit max timing to 39 degrees and before ping test.
A dial timing light makes this easy but masking tape and a little extra time also works just as well. If your dampner is not indexed you can put tape on dampner and use timing tab to mark an extra few marks on tape and read with new marks.