Getting closer on my project, opinions or suggestions??

Hello,
Great setup. It's similar to my current project. 1980 Volare, 360, Comp Cams XE262 cam, SpeedPro H116CP pistons, 596 heads topped off with a TQ carb and a 727 transmission with 2800 stall with 3.21 sure grip.
However, I'm caught in a dilemna. According to guys I've spoken to at swap meets, my intake manifold choice, an Edelbrock Performer, will not make the power I'm expecting. Having said that, I have available a stock cast iron 1970 340 intake manifold, and a Weiand 8007. I've been told the stock cast iron 340 intake manifold will outflow them all. Any opinion will help with these final steps to completing my project.