okay I have an 440 hp motor with an casting date of 11/23/69 & a date code on pad for assy. date of F which is 1970 so my question is on balancing is the 69 440 motor balanced the same or Is one internal bal& one external I am confused I am wanting to use a 11" 143 tooth flywheel tht I have but I believe it is not balanced ????? so would this be a 70 or 69 internal motor?? is there any diff.