Thank you for the link (and the video link!) I think that I might have been wrong (still searching trough my books) but I believe this site might cast some light on this topic!
http://users.bigpond.net.au/Shackleton/rolls.html It appears that I have mistaken the Griffon for the Packard! Bad me!
“However, the firing order was different from the Merlin. A 60 degree V-12 with a 120 crank and paired throws has a number of permutations on ideal firing order, no one being superior to another provided the intake system is "tuned" for the firing order chosen. However, the exhaust note will vary. This gave the Griffon its classic "Griffon Growl" exhaust sound, not as sweet as the Merlin but still impressive!! Different valve timing contributed to the difference in exhaust note.” Etc.
viking