Swapping from mineral to synthetic oil
Has anyone swapped from a 50 weight mineral oil to a 40 weight synthetic and seen any performance gains? I will be swapping from a 15w50 mineral to a 10w40 synthetic in my 582 BBC. Just thought i would ask the question, i have always used a 50 weight mineral in all my engines and have been told numerous times to switch to the synthetic for the frictional benefit and free HP gain. Was told around 10-15 at 7500rpm was typical.