the summit carbs are made by holley for summit racing, and are essentially the old 4010 carbs that holley put on the market years ago, but eventually pulled because they didnt sell that well. they are a good carb though, i like them better than the original holley design as the summit carbs dont run fuel through a gasketed area.
i also like the edelbrock 600 cfm carbs as well, a friend of mine and i have a total of 7 that are various ages, the oldest being about 10 years old, and none of them have any issues. i also agree going with a 600 cfm carb is right for your combination, and i recommend using either a performer rpm or weiand stealth intake.