want to build my ws6

I have a 98 ws6 transam with the slp ls1 engine it has stock 335 HP I wanna push tht 2 400 HP what are some simple things that can get me ther any advice

Welcome to AF. Got a set of near perfect gold center wheels with the W6 center caps, for sale. For mods I would suggest googling modifing that engine, there have been numerous articles in Hot Rod and Car Craft pertaining to this.