340 Intake manifold recommendations

Not sure single plane is right for you. I’m not sure what a stock thermoquad intake goes for, but as to performance you can get more out of them than most people would believe. I know I can buy a stock 68-69 340 intake for $100 and with a bit of cleaning and cutting the divider down run mid 11’s. They are heavy, but pretty cheap and can make enough power to make you go 8 3/4 shopping.