Hi from Australia. I am not too good at this IT stuff - would rather play with cars but I need some help and hope one of you guys can give me some advice.
I don't really know how these forums work or even how I find replies - 60 people looked at the last post I did but I can't find if anyone was able to offer any answers to my problem.
So here is what I need to know.
I have a 1977 Blazer 4 x 4 non-Californian which I bought here in Australia in 1979. It has a 400cu small block with a genuine GM HEI Distributor and I am replacing the spark plugs and I need to know the correct spark plug gap.
Hope someone can help me with this.

 

I looked up your application at Champion Spark Plugs, one of the oldest spark plug manufacturers in the US, and found that the gap for their copper core, i.e., common, plugs is 0.045 inches. (see below)

Often spark plug manufacturers will also list the gaps.

Good luck!

https://www.championautoparts.com/fi...ults.html?type[value]=2%2C8&type[label]=Car%20%26%20Truck&year[value]=1977&year[label]=1977&make[value]=47&make[label]=Chevrolet&model[value]=421&model[label]=K5%20Blazer&subBrand=bbkh

 

Thanks so much christine_208 - that's a great help.

 

You are very welcome. Be sure to keep us updated!