I have checked on some blocks, and tore up blocks that did not have torqueplates during honing: I have measured appx .001" of distortion with / without plates during machining, but seen bigger variations with or without maincaps installed (though in the bottom of cylinders, not that important). In a 502 bbc block which is a high quality block I could not find any distortion after use, and with a 414 LA 12.5:1 stroker done without honing plates the rings had made a clean polishing all the way around after only a few miles of street driving (blew a headgasket, so took it apart). If working with an SBC it should be used, when measuring it looks like the pentastar. However, I think the most important is not the plate but to get the threads stressed. So if I do not have a torque plate I use bolts and spacers to stress the threads, seems to work well (enough for a street job). My