1967 L71 Spark Plugs

[Gary C.]

Gents,
What is the recommended Plug for the L71, not cold climate . I have ACD N43XLS. They have been ok in the past. I now need a new set. The book says R43N. Are they available in the US?

Gary
Perth, Western Australia

[Joe L.]

Re: 1967 L71 Spark Plugs

Gents,
What is the recommended Plug for the L71, not cold climate . I have ACD N43XLS. They have been ok in the past. I now need a new set. The book says R43N. Are they available in the US?

Gary
Perth, Western Australia

Gary-----


The AC 43N is no longer available from GM or ACDelco. Even the R44N is no longer available. You might be able to find a set of 43N on eBay if you want to go that far. I'd continue to use the plugs you are using if they perform satisfactorily.

[Duke W.]

Re: 1967 L71 Spark Plugs

In general OE plug heat range spark plugs are too cold. Small blocks typically have heat range 4 and 3 for big blocks. Those who have dealt with these cars for decades have learned that heat range 5 is best for normal driving including long road trips for both engine types.

Your car originally had the non-resistor 43N, but most non-resistor plugs have been discontinued. The best current replacement AC plug for your engine would be the R45XLS. If it's available in a non-resistor type (45XLS), use those.

Duke

[Gary C.]

Re: 1967 L71 Spark Plugs

Thanks very much for input.