I personally am having some trouble finding exact specs on the 704 carb.. comes back as Holden. You in Australia? Also as for the 702 carb being better, that i dont know. But, when rebuilding one, you can make either work for you by putting the right parts in it. Jets, rods and such can all be gotten from cliff. Hell the carb on my mildly warm 350 is from a smog era truck, and it runs great because i specced it out the way it needed to be