It is a long time since I read up on this but
afaik....
The main advantage of using the early crown chassis is (something like) you can rebody pre-'72 cars and they maintain that build date.
However, the rego is usually something like >1971 Jaguar Rebody<
i.e the car it was.
not the car it has been made into.
Consequently, there are some things in the ad that may be problematic.
Fortunately the Cobra Car Club of Victoria is having its Monthly meeting this Wednesday, you can get many opinions - some of value
www.cobracarclubvic.org.au
LoBelly