Jump to content

Spark plug cross reference???

Recommended Posts

Sorry, I went thru a very extensive 'Cross-reference' list and could not find a P-4 listed anywhere. (There are 10mm plugs in the list tho, go to far right side to see size)

Here's the link if you want to check, but I want to warn you it is a very big list and takes awhile to download and search thru.


Link to post
Share on other sites

My 1962 AC conversion chart shows the Autolite P-4 to be equivalent to AC 104 and Champion Y4 and Y5, and the Autolite P-6 to be equivalent to AC M8 and Champion Y6 and Y8. For your Packard, the 1962 recommendation (with the gasoline of that era) was for AC M-8 for light service, and 104 for normal service.

Have you considered just going to the Autolite website and getting a current recommendation? I've had excellent luck with their plugs, and additionally like the fact that the shells are not cadmium or bright-plated which makes their appearance correct for your vintage. One supposed advantage of getting current recommendations is that changes in product and gasoline are taken into consideration. Can't assure you that is true, but that's what one plug manufacturer told me a while back.

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Create New...