Don't know if it's legal, but you would more than likely need an engineers certificate, since the EA series never had a V8 it.
EB/ED V8, or EF/EL V8? (EEC-4 or 5), cheapest way to make it happen would be to go for the EEC-4, not a lot of body mods required.
You are looking around the $4500, for an engine/g'box conversion. If the people you get this off are any good they will throw in the front cross member.
About $500 for a matching car harness complete down to the smartlock. Then I'd fit the tibbe keys into the locks, about $120.
When you get round to doing it give me a yell, I have a V8 cluster for sale.