I have installed a ready to run MSD distributor and they are saying in the instructions not to break in with synthetic oil and to run something like a standard velocity 10-30. I am currently running synthetic and would like to know if anybody has had experiance with this. I just changed the oil and you know how expensive synthetic is. Thanks.

..a standard velocity 10-30...

Sounds like an old rifle cartridge, made obsolete with the advent of the 30-30...

Are you talking about cam break-in? I have never heard of dist break-in per say... Most of the warnings of not using synthetic stem from old school beliefs and don't hold a lot of weight these days although a lot of folks still buy in... Here's the directions for your dist I believe.. http://www.msdignition.com/pdf/8360_frm%2023793.pdf I didn't see any break-in recomended...

I installed mine and I run synthetic, it's been out twice and looks fine.... But, it's your call and $$$.

At the very least, I'd coat the dist gear with cam break-in lube.

If you're really concerned, you could drain the syn oil into a clean container, cover it, and save it for later. Filter, too.

The molecules for Synthetic Oil are engineered to be identical..
Dyno Oil or Orgainic Oil molecules are different sizes and have more friction.

The idea behind any metal gear break-in is to match the 2 surfaces.
This is done by friction.

Synthetic Oil does not provide enough friction to properly wear both surfaces.
The first couple oil changes on an engine break-in should be done with cheap Dyno oil, 10-30 or 10-40 depending on ambient temp and expected horsepower.

..BTW - it's viscosity.. (the property of resistance to flow in a fluid.. thickness and ability to coat)..
...not velocity.. (speed or the quickness of motion)

these are opposing concepts

Dyno Oil
This is very important for cam, ring and crank break-in..
It sounds like you had a running (broke-in) engine, and just replaced the distributor. (it's just bad timing on your recent synthetic oil change)

I agree with BPOS, break-in lube or molly lube is a good idea, but it will sludge your oil, and needs to be replaced soon anyway, (another reason to use cheap Dyno Oil..)

98% of all distributor break-in's go smooth..
The majority of that other 2%, are people who tried to cut corners..

it's not a big risk, buy the risk does exist.
How's your Karma today?