Can the Karsten anser be ordered with a heavier head??

Short answer is yes. However, you can't specify a specific weight. The heaviest will be a bit more than 350g for the Anser type head.

I spoke to a Ping Rep the other day and was told that during the casting process (Karsten series) they'll inevitably end up with fluctuations in weight. This mainly due to micro bubbles that get trapped during the casting. This is why it costs $90 vs. a milled Redwood at $250.

So when you order through your golfshop, just tell them to ask for the heaviest head along with whatever customizations you want (e.g. loft, lie and length). PS - Ping also does 1/2" inch increments in length which is cool. No extra cost and should take about a week.

Cheers,
ML