A torque plate is a large steel plate that is bolted (and torqued up with a head gasket) to the top of the cylinder block when machining operations such as cylinder boring/honing etc are carried out. Its purpose it to simulate the stresses applied to the block when the cylinder head if fitted, making machining operations far more accurate. It is quite surprising how much a torqued cylinder head will distort the bores, especially in engines with only 4 bolts per cylinder (such as Ford 6 & 8 cyl engines). We have witnessed bore ovality of .0005" to .001” occur when torquing the plate in place, so its use is mandatory in performance machining operations. At Atomic we manufactured our own torque plates and they are used on each and every one of our performance engines when honing cylinders to the required finished size.