I am new to this site, but not new to old trucks. I have a 40 chev pu and a 64 chev pu and have owned a 50 and 46 chev pu in the past. I have ordered the kit from cpp to convert my 64 to power steering. It says to use a ps box from a truck up to 87. My question is can a box from a car such as a mid 70's camaro or fb be used instead? What is the difference? The spline? Thanks.