General Maintenance & Repairs - 2000 Camaro SS smoking?

I have a 2000 Camaro SS M6 with exactly 148,649 miles on it.

I never beat on the car at all and I've had it since 2002. I've never actually done what i'm about to explain, but since I did I noticed something.

My friend came over and i pulled the car out of the garage. It had been sitting for about a week without start. When i started it, no smoke. But after a min he revved it to about 4000 rpms and white looking smoke came out the tailpipes? It stopped smoking after he stopped revving and no smoke at idle.

3 days later i turned the car on and it did the same thing. I reved it after starting it cold. Smoke came out again. I figured i would drive it this time. I drove for about 10-15mins and came back home. As soon as i got home and revved it up to 4000-4500Rpms No smoke...Why would it not smoke after driving the car and warming it up?

Do i have a serious problem, or is it because my exhaust is old or something? I have a Y-pipe that goes to a flowmaster i bought in 2002. Could that just be old?

Car runs fine by the way and no leaks in my garage.

Any ideas, should i be concerned?

I don't think it's an issue it will always do that at a cold start I feel like that's 100% normal however It might be bc your cat isn't hot yet once it's hot it burns the vapors and so you wont see any smoke ... But I don't think it's good to rev your car that high after cold starts

Yeah I wouldnt sweat it. My 2000 SS smokes too when its cool or hasnt been driven in a while....even after driving it 15 miles or so when its cold. Runs like a champ..this is common as far as I know.