Re: 3.0 liter sparkplug.
AC-R43T is equivalent to the AC-MR43T. look for that if you want AC delco.
NGK BR6FS has stock #4323, sometimes the stock # is more easily found.
You can also use NGK v-power plug YR5 stock #7052.
I would recommend the v-power YR5 before the BR6FS, both before the R43T. All are $2 plugs.
The RV15YC4 doesn't cross to a R43T, nor does it cross to a BPR6FS, according to sparkplugs.com. It may be a hotter plug so I would be cautious using it. Champion RV8C is what is equivalent to R43T and BPR6FS.
