I think, as stated by all others, is that you are enjoying a well running normal 350 with a basic gear and rear end set up. It looks nice! Sounds like your only "performance" mod it the 4bbl. Not sure about that cam. No mention of what heads you are running or if you have duel exhaust (stock log type manifolds?) etc. Making 300hp with a 350 isn't hard but just swapping a cam and adding a 4bbl isn't a guarantee and depending on how its set up you might even hurt things down low. And the AC is stealing a few horses even when off. I would bet you are not making 300hp. All that being said if you abuse it enough you'll figure out how to get that wheel to spin.
If you don't care about gas mileage you can add of few of those other performance pieces and change the gears and you will really impress the teenage boys at the Dairy Queen when you leave a nice patch!! Even with your 350!!!
My tired old stock 350 likes a little sand at the start. But then she really burns tire.