1969, L71 Spark Plugs
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Racer
Joined: Jun 2019
Posts: 276
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From: Florida
1969, L71 Spark Plugs
I searched for recommended plugs, but I didn’t find what owners are using in their BB, 435hp cars.
I have seen NGK BR6ES and BR6S used, but in cross referencing it is all over the place as far as the heat range. Some say 4, 5, or 6. This is a street driven car with occasional “fun” driving.
What are you happy with? Thanks for any input.
I have seen NGK BR6ES and BR6S used, but in cross referencing it is all over the place as far as the heat range. Some say 4, 5, or 6. This is a street driven car with occasional “fun” driving.
What are you happy with? Thanks for any input.
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Racer
Joined: Sep 2010
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From: Alexandria VA
The original equipment plugs were AC heat range 3, but heat range 5 would be better for how we drive the cars now. i used Champion heat range 13 plugs for casual driving in both a L-71 and a detuned ZL-1.
1967 Pedal Car Champion
Joined: Mar 2020
Posts: 9,201
Likes: 4,295
From: US-PNW
I searched for recommended plugs, but I didn’t find what owners are using in their BB, 435hp cars.
I have seen NGK BR6ES and BR6S used, but in cross referencing it is all over the place as far as the heat range. Some say 4, 5, or 6. This is a street driven car with occasional “fun” driving.
What are you happy with? Thanks for any input.
I have seen NGK BR6ES and BR6S used, but in cross referencing it is all over the place as far as the heat range. Some say 4, 5, or 6. This is a street driven car with occasional “fun” driving.
What are you happy with? Thanks for any input.
I use NGKs in both my 427 and 454. The 427 runs BPR4ES (approx. R45XLS equiv). My cars are used mostly around town and some country roads but a lot of time is spent at low speeds and not extended highway speeds. The hotter plug works well. If you are mostly at highway speeds, choose the NGK 5 or 6.
Last edited by barkingrats; Mar 15, 2026 at 07:20 PM.
1967 Pedal Car Champion
Joined: Mar 2020
Posts: 9,201
Likes: 4,295
From: US-PNW
One more comment: the plug's heat range has no bearing on how hot the spark is. The heat rating is how quickly the plug itself transmits heat to the cylinder head. A colder plug can transfer heat too well and will build up deposits because the porcelain doesn't retain enough heat to burn them off while a hotter plug can retain too much heat in the plug and become a source of pre-ignition (pinging).
