I'm crossposting this with the Impala SS mesage forum, so if any of you read both, sorry for the redundancy, I just want to see your opinion on this matter.

Hey guys,
Time for another oil change and I decided to stop using Mobil 1. The two oils I am looking at are:

1. Red Line 10W40
2. Royal Purple Racing 41 10W40

I am unsure which to choose. I know Red Line is based on an ester stock, which is the best possible synthetic stock (unlike other synth oils like Mobil one which use PAO stock). Also, I heard that the Royal Purple Racing synthetic oil line is also based on ester stock. So I have to choose between the two oils. So far the thing that is making me lean towards the Royal Purple is its availability, price, and purple color

Anyone have any experiences with these oils?

PS you are probably wondering why I want to run 10W40 as opposed to the recommended 5W30. I found over the time of owning two LT1 cars that as these engines get older, thicker oil helps quiet some of the annoying valve train noises and makes them a bit less sluggish, especially in warm weather. I have been using Mobil 1 15W50 in my camaro since it hit 95k and sold it at 107 with a better running engine than what i started with. Anyway, I do not recommend running such high viscosity with a mineral oil of course, synthetics just flow so much better