I should have asked if there where any future plans for the build such as headers and cam and gearing or if you are still having to use your smog equipment and EGR. There was a used street dominator on here for sale a while back, they are a good choice too. A performer with the 600 carb you mentioned properly tuned would well be worth the effort. Most of the ones I have messed with we used the hated and maligned quadrajets on with a little extra air door tension, they have very good street manners.
