Spark Plug Heat Range Suggestions

[Calif240]

I'm interested in getting some of your all's opinions on spark plugs and how much affect this would have on my engine, with regards to the heat range of the plug... I have aluminum heads, around 10.5 compression, and run 93 octane. She is a shade under 500HP at the engine. Plug needs to be .750" reach, 14mm.

I just had Champions in there, as recommended by Marsh Performance, but am changing them because I just had one go bad. I was going to experiment with the NGK and some other Champions, but looking at the heat range... can you guys give me your recommendation on what heat range you think I should be running, and also what impact this would have on HP (Does the right heat range get you +5HP? +10HP?)

Any opinions are appreciated.

Thanks,
Terry

[firefighter3931]

Terry,

Get a 6 series NGK plug installed....your engine will thank you.   

I used an NGK BCPR-6ES in my old 10.5:1 446 with Edelbrock RPM heads. 

I haven't used a Champion plug in over 12 years....not even in a weedwhacker ! 



Ron

[Calif240]

Many thanks as always, Ron!

[kamkuda]

Whats wrong with champions? 

[justcruisin]

I agree on the 6's, the recommended heat range plug for the e-heads is a 5 in NGK, I found it to be too hot for mine which is built similar to the OP's. Maybe a 5 on a  engine with less CR but the 5's showed signs of detonation for me at sea level.

[firefighter3931]

Whats wrong with champions? 

Since production was moved off-shore the QC has been poor 



Ron