Review on Center Locater Screws Bolt Style Spark by Jeremiah Small

Bought to test TDC on my 347 Ford Windsor. Victor jr heads have long threaded plugs and it would be nice if these threads were about twice as long to spread the load over the length of the thread. The inner shaft fits into the base, but the threads aren't as tight as they could be. I screwed the shaft all the way in and got pretty decent stiffness. The photos show the fully installed instrument with two time stamps applied with black marker on yellow tape. With the tool fully adjusted, I found a stop of about 20 degrees before and after, indicating my TDC mark was right on target. In general it works fine.