The base timing is set to a different spec. for the Calif. 5.0 HO.
Calif. engines: 10* BTC with distributor vacuum hose disconnected and plugged
Non-Calif. engines: 12* BTC with dist. hose discon. and plugged
These specs are for manual
trans. cars, there's 3 different specs for timing on Calif. auto
trans. 5.0s. and 2 for non-Calif. auto
trans.
1985 was a big year for all kinds of different emissions calibrations and it would probably take a bit of research to find the differences.
As for the Cobra, there's no mention in any of my engine specs about a Cobra engine. It is a nice emblem, but unless I missed something during all these years, there was no Cobra in 1985.