[FC] differential gears

[Phil]

I have a tech question,not sure if i asked this one before,but ,here it is,i have a 1962 corvan,I putting together a 110 HP 65 FC motor ,iam running a 260 cam,60 over pistons,iam not making a race van,just alittle peppie,I have have 205 x 14 tires,i want to dirve on freeway,not 80,but 60-70 MPH,and I want to keep RPM down to a reasonable RPM,and I don't want to chug around the city ether,i have a set of 355 gears and a set of 327 gears,before I install these gears,i want to make sure iam using the correct gears,i know everyone has there own opion on a set of gears to ues,but ,I just want to drive the family around town and on freeway,without overheating motor,thanks everyone for your info......