Make sure oil usage is indeed a 205, or else you wont have the ICP required for 600 on fuel. Its an all too common builder mishap with these injectors. Another member on here just had it happen, and unfortunately its his limiting factor. Take great consideration in who builds them, the truck will be a turd if they are built incorrectly. The 66 will get you right at what you're looking for, pretty cheap if you get a box stock unit from BW. (~66/73/.91) Other than that, the usual supporting mods (fuel system, etc.) and you should be there. You could honestly hit 600 on the stock trans for a little bit. I hit 570 on my stocker for almost 6 months and it held. But if you have the coin, do the trans anyway.