ISO: Pound Cake Crazy

I'm trying to perfect a Pound Cake recipe I found on the Web, the first two were horrible (yes, it's getting expensive) I've cooked and baked all my life, (not short) and haven't made a lot of Pound Cakes, I'm having trouble with small tunnels in the baked cake, it looks like the inside of a wormy apple. The last cake (3rd in 3 days) is much better, I want to get rid of those tunnels completely, I've tried everything, I switched to my KA mixer (usually use my old SB)thinking I wasn't beating the butter and sugar well enough, I think this was part of it, I'm using dry buttermilk powder for the buttermilk called for in the recipe. I have to use it for the Contest, I did find a section in one of my very old cookbooks, and it said tunnels were caused by undermixing, not enough shortening-liquid, and an oven that was too slow. I've eliminated all those things and still have a few small tunnels.

Any advice and help would be greatly appreciated.

Pokaseedes