what exactly needs to be done to use a tpi intake on the older style heads, according to the codes on the heads from the 350 i bought they are from a 1970-1974 350

You will want either an 85 or 86 model tpi as bolt holes fit the old style heads. the 87 and later you would have to drill the middle holes out to fit the old heads

85,86 or ANY year Corvette TPI intake will fit the old style heads.