4 ltr v8 rattle on accelaration

HI ALL , NEED SOME HELP IF POSSIBLE ?
V8 has a loud rattle /clacking sound when accelarating and disappears if you lift the pedal off the gas and drive very lightly .
VEHICLE IS A RANGE ROVER WESTMINSTER 2002 model v8 petrol

Returns as soon as you push the pedal , car starts hot or cold first time , all gears etc change smoothly .
Plenty oil and water and never been low on oil .
Any ideas , was supposed to be doing 180 mile round trip in the morning but can't use as it is as its a worrying sound and don't want to do damage

All replies gratefully accepted
Cheers all in advance

Welcome to the forum, could it be the exhaust gaskets? Can you hear where it's coming from when you've got the bonnet open?

+1 I had a similar issue it sounded like a machine gun when driven under load accelerating, going up a hill, and silent on idle, turned out to be the manifold to down pipe gasket blown on the block side of the gasket so no way to to see or feel the leak.

Stayed like that for 3 months till the vehicle went for serviced, the exhaust had to be dropped anyway to change the autobox filter so gaskets on both sides are changed.