Re: V8 spark plug fitment?

Posted by PackardV8 On 2016/8/13 21:24:29

Look on the head for number directly on top of the MIDDLE exhaust port in PLAIN VIEW.

6480407 = ALL 56.
440690 = 5560-80
440690 or 440689 0r 440855 or 440854 = 5540.

Seems that i recall some sccuttle buttle about EARLY 56's useing 55 heads. I'm not sure.

Also check BOTH heads incase someone only replaced one head or used miscellaaneous heads.

Best to also measure the thread deepth in the heads. THAT will overrule anyother possibilities.