So I ordered ngk laser iridium plugs off of rock auto and ngk wires, but they only sent me 4 Tailing plugs, so I went to my local orielly got 2 leading plugs but the numbers are different and the bottoms look different. The tailing plug reads RE9B-T and the leading plug reads RE7C-L. What I'm asking is if it's okay to use them together? Is one hotter than the other will it mess my engine up??

 

Those are the correct spark plugs.

 

Awesome thank you

 

Be sure you put the right plugs in the right holes.
T=Trailing (TOP)
​L= Leading (LOWER)

 

I made this for my own benefit.