I read an article years ago about a guy who mocked up Hemi valve covers on his big block. Ran the plug wires through them and on to the proper locations. I remember the pics looking OK at the angle they were taken, but I can't imagine you'd fool anyone who was up close.
If anyone has a pair of Hemi valve covers they'd like to donate, I'll be happy to recreate it on my car and do a write up.
Anyone? Anyone? I'll pay $21!