I think that would be a seriously tough install - you'd need to move the firewall, splay the frame rails, and who knows what else. Your tranny wouldn't be able to handle the V8, so you'd need to modify the trans. tunnel to accomodate the 500E tranny.
Sorry not to have better news for you, but this is just some of the stuff MBZ did to get the M119 into the W124 chassis
