Whole foods. Look at LV's grocery list in the Nutrition section, stickied at the top.
I'd also go in that forum and post "hey, i'm gaining strength, but no size" and the post an average day's food intake. EVERYTHING you eat in a normal day, including portion sizes.
Ideally, you should go to a site like and input your food for a few days. You say you eat a lot...but your lack of size increase tells me its still not enough.
that means either your idea of a lot isn't really a lot...or you've got a pretty fast metabolism, and simply have to eat even more to pull this off.
I'm already assuming you're eating 5-7 meals a day, and have an idea of what your protein, fat, carb and calorie intakes are like.
If not, the last thing you need is ANY supplement. Supplements "supplement" your diet, and if you're clueless about your diet, how do you know you even need to supplement?
Its like saying "My car won't move, so I'm going to put a super charger on it" when all you really need is to fill the gas tank because its empty.
your body really is just an organic engine. if there's no leftover fuel, there's nothing to build muscle with.