You could contact Wilson Manifolds and see what they would charge to CNC-port a pair of anyone's 2V heads to a 4V size. They do this every day. Note that unless you are running a big-inch stroker Cleveland, 4V ports are usually considered too big for proper air velocity, or unless you regularly rev above 7000. Which is often disaster for a stock lower end.
All Ford/SVO Pro-racing NASCAR heads after the initial 1980 A-3s used smaller intake ports (SVO 302-b & others), and the Aussies actually cast up factory iron 2V closed chamber heads for their pro racing, which should tell us something.... 2V heads run 2.08" dia intake valves which are much larger than the biggest a 350 Chevy (with comparable power) can use.
I have run 2V intakes on 4V heads, and up to about 5000 rpms (near redline for a stock lower end) this works OK. At 5000-5200, power will nose-dive. If you don't plan to be up there in revs very often, a "mismatched" intake will do just fine. The big gains in aftermarket heads for non-pro-racers are the closed combustion chamber, the mechanical valve actuation system and the 32-lb weight savings each, not bigger valves and ports.
All in all, it sounds like your most economical approach may be to buy known 2V heads and a good matching intake, and sell your present intake on E-Bay rather than trying to reuse it. Good luck either way.