Howdy everyone I am new to the forum. I am looking into purchasing an xjr in the next couple months.

How far has the aj26/27 engine pushed on stock internals, stock intake and cylinder heads? I highest horsepower I have seen quoted is arround 480 hp.I would really like to make more than that, at least 550 hp. Is this achieveable? I have no problem with fabricating one off parts and using a standalone if need be, I just want to know the engine can take it before I get to excited. Also has anyone ever turboed an aj26/27?

Thanks