We change a lot of front main seals and oil pump cover o-rings here at OTRAMM. Holding the crank pulley while torquing the bolt to 300+ foot pounds has always been an issue. Over the last few years I've gone through several iterations of the tool we use at the shop. I've finally got it just how I like it. I figured other 80 Series owners would likely be interested as well so here they are! They're 3/8" steel water jet cut and then the 1/2" square drive is broached in for a precision fit on your breaker bar.
1FZ-FE Crank Holding Tool V2.0
Crank Holding tool for loosening and torquing the crank bolt on a 1FZ-FE engine. 3/8" steel, water jet cut, and broached for 1/2" square drive. New for version 2.0 we added a broached 3/4" square drive for those really stubborn crank bolts.