I used to take it to increase intensity in the gym, but now I only use it for cutting. While bulking I keep my fat in check with mostly light cardio with a little HIIT. I never do cardio on leg day or even the day after sometimes. Most people get better results if they do it on their off days from lifting or at different time of the day.
Some say ephedra cause excess cortisol secretion by the adrenal glands, others say it is anti catabolic. Personally I found it doesn't do much for me when bulking, yet I still made some good gains while on it. Honestly I'm not crazy about the sides but those can be avoided with reasonable doses (ex half a 20 mg pill to start) and time off to replenish your adrenals (ex2 weeks on 2 weeks off or every week take 2 days off of every stimulant including caffeine).
So I wouldn't recommend it using ECA while bulking, but you can give it a try. IMO You will have better results if you just dial in you diet and add a little cardio. Not as easy as popping a pill though LOL.
Thats my experience. Hope it helps.
A word of advice; seek advice from those with similar body types. For example I always see something like this, an ectomorph or hard gainer telling an endo/mesomorph he needs to eat huge amounts of food. The result, the endo/meso whines up looking like my avitar.