I have tried this method before, and it does work. It won't however, be exact. It will get you really close, but you will still need to get the timing tape as mentioned. Summit has them for about 8 bucks.78jeepstang said:Yes you can buy 'timing tape' as I believe its called which is basically what you're looking for. Pretty sure you can get it through places like Summit or a local speed shop.
Alternatively, i've heard of people timing their engines by using a vacuum gauge. You hook the vacuum gauge up to a source of manifold vacuum and advance the distributor to where the gauge peaks, then back it off so the gauge falls 1" of vacuum. I've never tried this method but heard it mentioned a few places, so your mileage may vary.