D66 Carbs?

I am thinking a pair of Eddy 600 1404's set up for jetted for dual quad operation on the D66 for my 408, I had the manifold flowed at 498hp,carbs are these in fact:
http://www.ebay.com/itm/350921094019?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
as I have a mate here with 500's on his 340 and they kick butt!
What do you reckon?
Brian
Queensland
:-k