Cars vary in size , running from 1 : 87 ( generally the older cars ) to 1 : 64 in scale ; .
Cars all run on track of approximately the same width , and are generically referred to as HO slot cars .
Cars vary in size , running from 1 : 87 ( generally the older cars ) to 1 : 64 in scale ; but they all run on track of approximately the same width , and are generically referred to as HO slot cars .