Just to set the stage. I have a 289 bored out 30 over. Edelbrock Performer heads,Edelbrock 4 barrel intake, mild hydraulic cam,roller rockers, windage tray, Edelbrock high flow water pump and electric fan. So what carb? I live in Canada ...about 3440 feet above sea level. I happen to have a holley 570 Avenger I got for a song at a garage sale but I'm thinkin maybe its not enough... so I'm interested to see what you all think...Thanks