Is is possible to remove the pan on a 4x4 van? 460 engine developed a deep knock. Almost like two round 2" dia wood dowels being knocked to together.

I thought I might remove the pan and see the if I can see anything.

I can hear the knock at idle but is loudest at about 2000 RPM. Engine noise drowns it out after that.

Tomorrow I', gonna get a hose or long screw driver and listen for where it is coming from. Seems loudest coming from rear of engine. Can hear it well while underneath vehicle.