from www.crower.com/misc/faq.shtml
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Use of Synthetic Oils
Crower does not recommend the use of synthetic motor oils in any racing applications, particularly hydraulic and flat tappet camshafts. The minimum gains in horsepower are offset by the excessive wear to cam and lifter surfaces. Crower recommends Kendall GT-1 (20W50) Petroleum based motor oil in all high performance applications. If your manual suggests running synthetic oil, then do so. We have found, however, that the benefits do not outweigh the costs. For additional information click here! < http://www.atis.net/oil_faq.html >
There "here!" link is posted next to that, which I did not read. Since Crower is what I bought for my car, I'll post them. I'll also look for others, I believe Skunk2 feels the same way.