Re: Cardio and muscle mass...
Yes, want you want is a clean bulk. It's more difficult than a typical bulk because you have to track your calories carefully.
You want to have enough calories that you can gain, but not so many that you gain fat. So you can try this:
calories needed = 15*(your bodyweight)+100.
That's an estimate for an active person gaining about 2lbs of muscle a month. If you're not gaining or getting fat, adjust the calories accordingly.