Guys,
For your FE's, especially running solid / flat tappets, see Crower's comments (literally) below. They're not big on synthetics:
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.
© 2005 Crower Cams & Equipment Co., Inc.
Phone: 619-661-6477 · Fax: 619-661-6466
Regards,
-Michael