AirborneSilva

So let me see if I understand this, if I have an R45 now and want to go with a hotter plug I would get an R43, for instance, is this correct? Thanks

toobroketoretire

No, the higher the number is the hotter the spark plug is. An R45 is considered to be the hottest plug recommended for a 350" small block.

AirborneSilva

Thanks a chart I was looking at on another site seems to say different. As for the recommended heat range, I'd agree if my motor was stock

EDIT: Now I'm reading on a different site that a 46 or 47 would be hotter, so much damn conflicting information but it's what I thought...

gkull

All my stock headed gen I chevy builds get Bosch Platinum+4 Spark Plugs (short reach peanut plugs) All my aftermarket 3/4 inch get autolite platinums.

The spark jumps off a tiny point easier than those old crappy erosion prone plugs

The 4 tip plugs make it so you don't have to index the plug to get the best flame travel.

Modern plugs last for many years

AirborneSilva

Do you have any recommendations for a hotter plug? I've searched for AC R46 and 47's but not having luck.

TheycallmeDave

I had nothing but problems with Bosch Platinum plus 4 plugs in my 2002 Hyundia SUV. Got thru plug wires quicker . Maybe the Chevy Heads can tolerate them better.

MelWff

Why would you possibly want to run a plug that hot. The hottest the factory used was 45 the coldest 43.

pws69

Unless you have bad rings and are trying to burn off oil, it makes no sense!

gkull

Most stock cheap plug wires are prone to blow through leakage with HEI ignitions. Just start your car in your garage on a dark night with your hood up. You really need quality wires.

AirborneSilva

Guys, I have my reasons and this is not a stock motor as I've already said. One or two hear ranges higher is not going to melt my pistons!!! If you can't answer the question then thanks for looking

Ironcross

What you may find is that the R-45 is hard to find, therefore use R-45S.....Perfect for a 1970 LT-1 power...and gap the plugs at .035....otherwise do what you want.....

AirborneSilva

Now I remember why I usually don't ask questions like this in the open forum

REELAV8R

Yes, frustrating sometimes. I use and would recommend NGK as a quality plug. You can get whatever heat range you would like.
Use this chart to decide the type you would want.
http://www.ngksparkplugs.com/techinf...tnumberkey.pdf

For instance a BPR6EY would be a 14mm projected tip resistor plug with a 3/4" reach and a V groove electrode in the heat range of 6. Lower number hotter higher number cooler.
Plenty of reasons to run hotter plugs. Cold weather is one. More heat in the chamber and you still get good burn even when the water does not come up to temp. I go as hot as the engine will tolerate and not detonate.

resdoggie

Be advised that heat range numbers can be opposite in direction depending on the plug manufacturer eg AC heat range goes down in number for colder plugs and NGK goes up in number for colder plugs.

AirborneSilva

Thanks, a real answer with a real solution

AirborneSilva

LOL yeah that's what was confusing me thanks for the reply

Ironcross

except they all start at the same temperature no matter what heat range........

AirborneSilva

Kinda like a woman

Kacyc3

Every manufacturer is different and probably why there is so much misinformation, go to the manufactures website and read up. AC Delco the number goes down for colder plugs and NGK the number goes up for colder plugs.

AirborneSilva

Thanks