I don't own a Skyline (YET!), but I was just looking at the specs for a Commodore..
Executive 3.8L outputs 152kW / 305Nm
SS 5.7L outputs 235kW / 465Nm
You should be able to kill an Exec, I dunno about an SS. And I'm speaking purely from these stats.
Cheers,
Tim
*EDIT: Yep sorry forgot to include weights.. the Comms weigh about 1.6T