If you're trying to squeeze the last bit of HP out of a race engine, yes. The boring job doesn't need the torque plate, but it's a good idea for the final hone job. A small block bore assumes a measureable pentagon shape when a torque plate (or a cylinder head) is bolted down due to 5 bolts surrounding each cylinder, but the effect on a street engine probably isn't going to be noticeable. If I'm charging somebody $15K or more for a round track engine, I'm definitely going to do the final hone job with a torque plate attached. Of course, that engine is going to be a worn out antique after 1K miles or less, sometimes a LOT less!
Jerry
