I dunno man but nice mower in your avatar!!
I have not used it in a 6461 but I use them in my 10515's with success. They are a direct replacement for the cj14. It may actually be better than the champion but that is simply an opinion of my own personal taste.When I told my local Toro shop I needed a plug to replace the Champion CJ14 currently in my late 80s Lawnboy Commercial Model 6461 he gave me a NGKBPMR4A. It looks about the same but would feel better if someone out there has used the NGK plug successfully in their 6461. Thanks.
Yep, that's the plug for the Duraforce. All my F's run great with the CJ14.i checked the specs on my 10323 on the bench right now, lawnboy sez use the bpmr4a