synthetic oil

You could always just buy a zddp additive.

ZDDP=zinc dialkyldithiophosphate is a zinc based additive/compound that helps provide anti-wear/anti-scuffing protection for engines with flat tappet cams/lifters. It has been systematically eliminated from standard motor oils, as when it burns in the combustion chamber (in worn engines) and exits, through the exhaust stream, it compromises the function/longevity of catalytic converters, providing a marginal/questionable environmental benefit while causing a truly damaging compromise of lubrication for older engines and other engines running flat tappet cams. Some suggested solutions have been to use oil formulated for diesel engines (currently still have some zddp, but may change soon) or use specialized racing oils from companies like Schaeffer, Royal Purple, Joe Gibbs, Brad Penn, etc. These racing oils will likely, eventually (if not already) be labeled "off road use only" meaning that technically you will be committing a crime by using the oil to save your engine, even though it is not environmentally harmful when no catalytic converter is involved! I believe there are also additives available over the counter to replace the zddp.
My $.02,
Gene

Just make sure you have absolutely no oil leaks. Even slight drips with conventional will turn into big runs with synth. I was running it in my '66 with a 5.0L and I switched back to conventional cause I was losing oil. For whatever reason Synthetic is really good at finding places to leak out of.

According to my builder, and an article he showed me from Popular Mechanics, the zinc is only necessary for initial cam/lifter break in with flat tappet lifters. Most oil has some zinc in it, but ideal for the break in is 1200ppm. Regular oil is much less than that. A bottle of the ZDDP additive (~$10), in the first start up oil should do it. Once the cam/lifters burnish the surface of each other, any quality automotive motor oil provides adequate lubrication. The article specifically recommends against diesel, motorcycle or other oils not made specifically for automotive gas engines, as they contain additives that really shouldn't go in our cars.

Valvoline VR1 has lots of Zinc also.

don't run a flat tappet, but know people who do and have wiped a lobe after break in. Also, know those who haven't and don't run oil with zinc. The $10/per oil change, or added cost of the other brands of oil are much cheaper than a new motor (or the cost to fix one with a wiped lobe), just my 2 cents.

From what i have read, if you change your oil like you are supposed to, regular oil is fine. Unless your wanting to change oil in the 7000 mile range. But, for the cost of 1 sythetic change, you could do 2 regular changes. and if your just cruising the car, i wouldnt worry about it.