The 273 2bbl and 4bbl use different linkage. To modify the 2bbl to fit a 4bbl will take some cutting and welding to get the correct geometry. It might be easier to get an aftermarket cable kickdown setup.
Is there a less expensive sorce for the cable kit than Year One?? That want $180 +50 for a aftermarket intake bracket !!!!!!! That seems rather high to me.