After making a pass my car will have almost 2qts of water in the overflow tank, when the car cools it all goes back in. Is this normal. I don't think it's lifting the heads, because it doesn't blow out of the overflow and all the water returns to the radiator from the overflow tank when cool.

85 degree day
water temp 210-220
18lb cap, stock radiator
turbo build, 900ish rwhp

 

Normal. But, the tank should be filled to a prescribed level when cold. If it's empty when it cools down, it can pull air into the system.

 

Thanks