What spark plug heat range do you run?

[jwright]

I am curious what heat range spark plug people are using. I haeva 350 (280 TRS package 1976). the book calls for AC-MR43T but they do not seem to have enough color after I pull them. I do have Mallory electronic ignition but I doubt that makes a difference. Any opinions out there?
Thanks in advance!

[Rootsy]

todays fuels just don't have enough lead in em to get a good plug color in a quick fashion... toss in a few gallons of torco, VP or turbo blue and run her... then do your plug checks...

i run 43's in my 350... i tried 44's and 45's and they did nothing to help clean up idle...

[Forrest]

I don't think that I would go any hotter than a 43. You can always go for a wider heat range plug. ACs and Champions tend to be narrow heat range plugs. I'm running NGK UR-5 which covers AC numbers R42TS and R43TS. NGK UR-4 covers AC numbers R43TS, R44TS, and R45TS.

Also, the NGK website has a neat crossover search feature that's worth checking out. Just put in any manufacture's plug number and bingo!

http://www.ngk.com

[Sam]

Great site Forrest, I just bought some NKG's and was trying to find out the heat range. I sent NKG a note via the site you mentioned.


THX
Sam

[Donzified]

Hey Sam , Wednesdays are" BOATIN "days.

"Spare props on early rides."

[Ralph Savarese]

does anyone use the Champion stainless sparkplugs I need to know a # for a replacement of AC Delco R43TS These darn plugs rot away in 1/2 season from dampness
Ralph