Quote:

Royal Purple XPR 10W40 gonna be OK in my 408 stroker motor making around 450HP?? Pro's / Con's on this oil?

I ran the racing 11 Royal Purple, 2 seasons and bearings showed no wear. Only problem I had it was so thin it would leak in places thicker oils wouldn't. Changed it at the track (due to leaking)went to Valvoline racing 20-50. Using Milodon 8 qt.Pan went from 10.10 with 5 1/2 qts Royal Purple to 10.21 with 6 qts Valvoline. 7 qts took it up to 10.26.

5438862-DARTIN62.zip (50 downloads)