I spoke to TRD who did Scranton's 1800hp 2UZFE steel block. They did a fancy 4 bolt conversion with angles bolts into the side of the block and a crank brace.
Personally I would not bother - we split two 2UZFE blocks while putting out about 1,100hp. One a four bolt conversion, one a crank brace. But that was supercharged - turbo's are kinder on engines.
Personally I would not bother - we split two 2UZFE blocks while putting out about 1,100hp. One a four bolt conversion, one a crank brace. But that was supercharged - turbo's are kinder on engines.