Uneven top and bottom temperatures

[pengyou]

I made my first double size cake in my new oven. The top came out beautifully flat - not. Single crack in it. I thought I took some photos but I cant find them. I set the top temp at 165C and bottom at 170C. As i said, the top came out beautifully flat, but the whole middle of the cake was a tad bit underdone, while the outsides were perfect. The center was still eatable. I was originally thinking the reason for the cake coming out so flat was the temperature difference. Any other possible reasons?

 

[Rocklobster]

Was the oven rack in the center of the oven? Maybe the cake was closer to one element?

 

[pengyou]

Thanks! They are as equal as I can get.