This is a good thread! First one I 've read in a while that didn't go off to Jones's.
I think that between the various posts outlining compression, cylinder head design, cam profiles, fireing orders, etc., the nail got hit squarely on the head. It is all of the above with compression that hits you like a hammer being the big dog.
Why does a 351C sound like a BB Chevy? Easy. Canted valve heads with very similar port configuration. I've owned both. The only difference I could discern was the pitch of the BB Chev was deeper. The general sound was virtually identical. I once had a sand drag Bronco, with a Boss 351C in it. I can't tell you how many times I got asked if I had a rat motor under the hood.
The FE sounds like no other engine I've ever heard and I attribute that to a cylinder head design unlike any other engine. I exclude the Cammer and TP, because they each also have a sound that is uniquely theirs.
As to could I pick out a MR or HR 427 S/O out of a crowd blind folded? In a heartbeat!!
Want a real laugh? I parked My Contemporary (w/11:1 427 S/O) out side of a restaurant once, out of sight of the front door. When I got inside, I got asked if I was the guy who just rode in on the Harley!!! Musta been those Butler mufflers!
There weren't any Harley's on the lot!!
Al