Replacement Carb for a 70 340

I’d use the Edelbrock AVS-2 650 & get the throttle adapter. Use the Edelbrock thick gasket to mimic the OEM gasket. It approximately .333 thick. That gasket will stop heat percolation of the fuel.
That’s the carb (1905) I am leaning towards. I have several thick gaskets I can use. Thank you rumblefish for your comment