Review on Spark Insert 14Mm 1 Compatible Buggy by Draek Villareal

Planning to install inserts for use on my VW 1600 dual port heads. Luckily I decided to drill out a piece of aluminum and to see how well the threads fit the inserts.Short answer, they didn't fit or even started to fit into a properly drilled M16x1.5 threaded hole.Very happy I did before drilling the heads did a test hole it's a much better product and design that works my review is based on over 60 years of automotive and mechanical shop experience much of it at VW.