340 rebuild

You will have to get those Edelbrock's heavily ported to make 600 HP. Intake flow is going to need to be close to 300cfm to support that kind of HP. Check with Shady Dell Speed Shop about their stage 4 porting for the Edelbrock heads. They will also shoot you in the right direction on your build. Also, sell that intake and get a M1 single plane or equivalent.