It's an old car with a big engine, not a good combination. On a sale to a regular buyer maybe £500. To a Ford enthusiast who hankers after such a machine maybe £1500-2000.
Insurers will only ever give you book value, which is very poor (CAP only goes back to 2003, and the equivalent model in above average co edition is only listed at a mighty £150). You can get an agreed value policy, but on a 19 year old car they're unlikely to accept that it's especially valuable and will want some kind of proof, such as an owners club valuation etc, if you're trying to insure it above book.
Best bet is to enjoy it yourself, take good care of it, and keep it going for future generations to enjoy.