Clark spoke about the Clarets today and said: "Since Sean has come in, whereas they were scoring plenty of goals and were attack minded, they were conceded a few. That part of the game they've been tighter.
"But they still have the top goalscorer in the division in Charlie Austin who I know very well from his time at Swindon. He is always on the move and is very similar to Jordan Rhodes in that a lot of his goals come from crosses when he gets across the front of defenders when they are ball watching and they don't have good body shape. His work ethic is terrific.
"The have got some other good footballers in the team too. They've got a young lad from Manchester City, the right back, Kieran Trippier, who is very high energy and quick, likes to break forward from their back and makes a lot of their goals.
"We are expecting a very tough game, but there's never an easy one in this division. It doesn't matter who you play, as Peterborough showed last week by going to Cardiff and winning."
Clark added: "Starting Saturday we've got five games in 15 days. Three of those are on the road meaning that we will have to travel before the day of the game which makes things even more difficult.
"It means that the majority of players we've got available, including the youngsters, will be getting some game time because of little niggly injuries, fatigue etc. over that period."
Sean Dyche also picked up on the theme of utilising the squad. "The games are crunched together somewhat and it's fair to say opportunities arise at any given moment, as it did for Kevin Long last week," he said.
"Keith Treacy is another who has been working very hard and coming along nicely. He has been putting the work in that is required to bring him up to match fitness and he is getting there. You can never tell fully until they get a start, but he is certainly improving and there is no doubting his abilities."
On tomorrow's game, he said: "Birmingham have a depth of experience in their squad and on paper they are a force to be reckoned with, but we are ready to take the game to them and get the result we all want, which is a win.
"It's a good sign that we are not giving a lot of goals away and the real positive is that we continue to create chances and you just believe as long as you do that the goals will come."