Be reeeeeal careful with the adjustable upper arms. When using them with standard length lowers, for every day driving it's best to leave them at the standard length too. When you start changing their length it rotates the rear end and changes the pinion angle. You really don't want to do that unless you enjoy changing u-joints all the time and every so often, the whole rear when the center housing cracks around the pinion shaft. You probably won't notice the cracks in the housing until under a full power up-shift, when it shatters. (giggles) yeah, been there, done that. Lots of pretty sparks. Hey, back then we didn't have anybody with experience to learn from.
Before you swap out the engines, wouldn't it be cool to take out the 305 in a blaze of glory? I used up a whole tank of n2o through a plate system with 150hp jets and it still runs. I wonder if it would take a 400hp shot?