Correct Engine Oil?

[moonshine_mike]

Bought my first Cuda in 1978. It's long gone now, but had it for about seven years. Always ran on CAM2 motor oil. Didn't have a logical reason other than the pro racers I saw using it. Today I run VR1 racing oil 20W50 in all my E bodies. Mainly high performance street cars. I don't even know if I can find CAM2 anymore. Haven't had any oil related issues yet (fingers Crossed). Never used synthetic. Never used any other brand except for engine break in.
Living in Arizona it's got me wondering:
Am I using the correct brand, chemistry and weight for the money or should I switch for something else to help engine life. Do any of the Mopar engine experts on board have some thoughts on best practices for engine oil on E body engine Mopars?   

[Cuda_mark]

I use Brad Penn 10-40 in my 426 Hemi

[Mr Cuda]

Oil weight is based on rod and main bearing clearance, and rpm.
 Failure to use the correct weight will cause problems IF the engine is driven under extreme and endurance conditions. Most engines are not used this way, so the effects of wrong weight oil don't show up.
 Brand is up to you.

[HP2]

Oil weight is based on rod and main bearing clearance, and rpm.
 Failure to use the correct weight will cause problems IF the engine is driven under extreme and endurance conditions. Most engines are not used this way, so the effects of wrong weight oil don't show up.
 Brand is up to you.

THis ^^^

My current engine is so tight that 5-20 is recommended for street driving. a step up to 10-30 for extended performance driving would be needed.

[moonshine_mike]

Great info. My eyes are opening. I feel embarrassed to see how much info there is available to me about selecting oil and that I never looked into it prior.
Turns out, at least two of my engines, a 340 and a 426 should have been running with 10W30 and not 20w50. I'll update appropriately.
Thanks again.

Is there any way to determine experimentally what oil viscosity to be using if you don't have the clearances? Or should I just use a default viscosity like 10W40 and hope for the best?

[tparker]

So the questions begged is, how much difference is there in oil? Other than additives, what would the differences be? It's not like each company has their own well. They buy oil as a commodity from the same sources I imagine.

I never thought about oil for bearing clearances, but always thought of it as a temp thing along with  a worn out engine, which I guess would be tolerance related. Hmmmm.... what does my build sheet say? Gotta double check. LOL