We are rebuiling our 351 Cleveland it's a 1973 motor. It's an original 2bbl carb setup and I would like to go with the 4 bbl carb. I was told the ports on the heads are different from the 2 to the 4. Would I have to change the heads then, or is there a 4v intake made to fit the 2v heads? Also do I need to change the cam?

Thanks,
Liz