Stock 1972 340 intake and Thermoquad HP limits..?

Any guess what the factory cast iron intake and TQ would be capable of supporting power wise? Lets assume a true 10.5:1 .030 340... Big valve "J" heads and a SFT camshaft... There is a 69 valiant here waiting for a 340 swap from a 72 swinger, the owner plans on making some upgrades but wants to keep the factory iron.