G'day Mate,
No the clunk should not come to the front of the tank as it will be kinked if it did & you will not get any fuel at all to the motor, try this test, get a clear drink bottle anything will do, as long as you can see whats happening inside, part fill it with water, hold it in your hand, & take it from behind your back on the right up & over your head to behind your back on the left, & watch what the liquid inside does, this simulates what happens to your fuel in the tank in a dive, the plane is travelling fast enough to stop the fuel from running to the front of the bottle, you will find you can do this at quite a slow speed before the liquid moves forward. so unless you have a tuning problem or you clunk is touching the back of your tank, your motor should keep running fine.