Wally,
Don't know what the rego rules are in WA but a 302 won't pass ADR 79/00 or 79/01 for emmissions. I'd check with your engineer exactly what Ford motor you can use for your Cobra.
Btw, I wouldn't pay too much attention to these Chev/Darksiders. Classic Revivals should be renamed Darksiders I think.
They're too quick to compare a 302 to a 350 LS1. They should compare apples with apples. If you can get a 302 stroke it to 347. When Tickford did this (was actually a 342 ci) they gave those LS1 thingies a run for their money, especially when a T3 TE50 weighed about 100kg more than a HSV. As for the weight a 302/347 it's about 230 pounds compared to about 185 for the chev. Thats about 20kg with Iron heads (chev uses alloy). Replace the Iron Heads with Alloy units and there's most of your 20kg recouped. Now you're really comparing apples with apples but I know what the Darksiders will say next; that all costs $$$$. True, but you'll get it back if you ever need to sell. Chev Cobras usually don't hold their value as well as Ford examples (however, this may change with the amount of LS1's now being used - who knows?). Some people can easily overlook that alloy is not as strong as Iron. If you took a close look at a LS1 block and compared it to a 302, a 302 is much smaller, especially around the caps. To get the same strength you need close to twice the amount of metal.
Can't wait to finish my car and line her up against some of these Darksiders!