Need spark plug education please

Ford supersedes part #s regularly. This exact spark plug part numbering issue with SP589 was discussed recently: (122) Spark Plugs | Ford Mustang Forum (allfordmustangs.com) That thread was for a 3.7 v6 though.
Ford CYFS092FT is Motorcraft SP551 which is listed on the Ford dealer sites as what's right for your car: Ignition System for 2019 Ford Mustang | TascaParts.com However, that's been discontinued and supposedly has been replaced by CYFS12YT6 which is SP589:
CYFS-12Y-T6 - Ford Parts Giant
CYFS12YT6 - Ford Spark Plug. 2018-22 5.0 LITER. Spark Plug. 5 | Lakeland Ford Online Parts, Lakeland FL
It's strange how some of the Ford dealers like Tasca don't list the part # that replaced the original but several other large dealers do.

Got into plug differences when I had my Corvette. Aside from all different widths/lengths, heat ranges will make or break your motor. See if I can locate modern updated chart that I’m thinking of… be back soon.

Something as this:

Braindead said:

Got into plug differences when I had my Corvette. Aside from all different widths/lengths, heat ranges will make or break your motor. See if I can locate modern updated chart that I’m thinking of… be back soon.

Something as this: View attachment 785949

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Thank you Cobrajet67 and Braindead for your time and reply.

I will put a sticky note in my owners manual to show SP589 / CYFS-12Y-T6 as the updated plug replacement for when the time comes.

Take care.

Bulleye said:

Thank you Cobrajet67 and Braindead for your time and reply.

I will put a sticky note in my owners manual to show SP589 / CYFS-12Y-T6 as the updated plug replacement for when the time comes.

Take care.

Click to expand...

Thank you for asking. Stay away from news these days so this is kinda like reading morning paper before going to work. Oops, don’t do that anymore either lol.

JBert said:

when the time comes, I think I would go to my local Ford dealer, ask them what is the latest recommended "OEM" plug, and buy those from them ... might be a few dollars more than Rock Auto but should eliminate any guesswork

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When it comes to getting plugs at a physical Ford dealership I would not ever recommend buying them there. I recall taking my 2005 F150 3V to the dealer to have them diagnose an issue and I had them replace 2 plugs that were broken and causing misfires. However, unbeknownst to me they were charging me $20 each plug so before I knew that I then ok'd them to do all 8. You can imagine the surprise with the bill for just replacing plugs.
Online I could have bought those very same Motorcraft plugs for only $9 shipped for each. That's $88 extra I paid for buying a set of plugs at my dealer. Never again will I do that. It's also another reason that I supply my own Motorcraft parts to them whenever I can to have them service my vehicle. If they weren't so damn greedy I would buy parts from them but other than things like tires and batteries which their pricing is usually unbeatable I buy the parts online and then hand them over to them to install.
My suggestion is send one of the online Ford dealers(Tasca, FordpartsGiant, Levittown, etc) an email asking them to send you a quote for the plugs for your VIN #. It'll list the part #, shiping price, and it'll also be hella cheaper shipped to your door at a steep discount.