To add to the insightful post that Owen Hughes (SVD) wrote yesterday day on VWs, I would avoid the Mofoco heads. The photos show lots of fins, and that's great, but what they are lacking is cooling air passages, I mean almost nothing. If the air's not flowing through the fins, they're going to run hot. I'm looking into this same subject lately, now that it's gotten hot and I fly in the 90's most of the time, and I'm tired of seeing 400F when I'm only 500' off the runway on the first flight of the day. I ran across a photo over the weekend from a Dec 2010 Hot VWs article that showed bottom views of 18 heads they reviewed, and Fomoco's weren't so great. On the other hand, the "Chinese" heads were awesome, lots of daylight between the fins, and by most accounts I've found, the quality is very high, and the price quite reasonable. DRD Aircooled sells them, and I plan to order some tonight. Whatever you buy, make sure you get stainless valves!
Another good chart that wraps up a lot of VW head details is at http://www.thesamba.com/vw/forum/viewtopic.php?t=573099 Mark Langford, Harvest, AL ML "at" N56ML.com www.N56ML.com
