Engine Spark plug surprise!

[My92cashtrap]

So I recently picked up a 1992 LX with a 347 stroker. Only 1000 miles on the build, but the car runs rich (drink gas, and is muddy in the mid-range). So I thought some basic points to check would start with the spark plugs. The first pic is what came out...the second pic is what went in to replace them.

 

[Dan02gt]

I would think a 347 would have aluminum heads. If so neither of those are correct. You will want Autolite 3924 plug. The factory style plugs do not thread far enough into the head to reach the combustion chamber.

 

[My92cashtrap]

Well that sucks...I already installed them.

I went down and picked up 3924s and installed them. I couldn't believe the difference in length. I'm amazed the car ran as good as it did with the short reach E3s.

Thanks again!