Smokes when starts up

When I start up my 1972 VW Beetle sometimes there is a large cloud (puff) of white/blue smoke. This is only when I start it and does not last. My oil level is OK, but it looks like something is not right. It still has the original oil bath air filter, but is not overfilled. I know that this can foul the plugs overtime.

I don't think the nieghbors like this display too much ( and either do I).

Thanks!