Originally Posted by CMcAllister


65 is the OE replacement. As the number get smaller, they get colder. We ran 55-51 back in the day. Same plug, nonresistor. Many of these numbers are NA. 63, 64 and 65 are still good.


51 is now 315
53 is now 300
54 is now 302
55 is now 38

You can punch the old numbers in the link below and it will tell you the new number

https://www.championautoparts.com/find-my-part.html