GMC 305e Carburator Choice

[DreamRyder1963]

My brother and I are starting to think about doing some slight performance mods to his truck. The truck is running perfectly now so this is just us brainstorming for the future. I have picked up a second intake for us to work on while he continues to drive the truck. According to 60-66 GMC Guy, a 500 cfm 2 barrel Holley is a nice choice for these engines. While we both like this idea, he is still in high school and getting ready for college so money is an issue. Would a 600 cfm Holley 4 barrel be to much for this engine? I tested the fit of a 2 to 4 barrel adapter this afternoon and it fits fine. I ask because I have a spare 4 barrel right now and this would save him a nice chuck of change.