Dennis,
With all the talk about rollers in the new 496 Mag and Ho can I use the Redline oil in this motor?
Thanks

The most extreme friction point on any engine is between the camshaft and a FLAT based lifter. The bearings and rings require much less lubrication. All of the advances in oil have come about to better lubricate the flat lifters and cam. One of the major advantages of roller lifters is that they don't require the same high quality oil as flat based lifters. The secondary benefit of this is extended oil change intervals.
Sure you can run Redline oil with roller lifters. Don't know if it is worth the extra cost though. 15W40 oil is good for a marine engine if you can't get Mercruisers 25W40.
Sincerely
Dennis Moore