I just purchased a 12v heater motor from Carter (supose to be correct application) to replace my 1954 6v heater motor on the fresh air deluxe heater. To make this motor fit I will need to drill new holes in the heater housing because the studs on the 12v motor are narrower than the 6v and I will need to make a new rubber seal where the motor fit through the fire wall because the 12v motor is smaller. Carter tech says he has never heard of the need for modifications. Does anyone know if there is a better motor for this application or is this typical.