Now that the 57 is out of paint jail and going back together before the interior is completed plan is to install seat belts in the back. Have three grand kids that all want a ride in Pop-pa's old race car. Two of them are 4 and 6, still using car safety seats. Oldest one is 16. Looking at Juliano's for belts but see there is a 60'' and a 74'' belt offered. Does anyone know if the 60'' belt will work with a child's safety seat with the belt passing thru the frame of the child's seat? Seems as if using the 74'' belt there will be a lot of excess belt at times with an adult in the back seat. Maybe over thinking this, not sure on length question.