Pinion angle with truck arm suspension?

[Operatorfailure]

I have a 68 c10 short step with a 5.3/4l60e, bone stock with 3.73s. I can't seem to find exactly how to set up the pinion angle to hook up the best. I have read some places to set it exactly in line with your engine/trans, some say to just have it nose down a couple degrees and no mention of engine trans. I know I am not making very much power in all reality and don't see why I couldn't hook up with street tires if I am only running 15.6 in the quarter. I know part of my bad times are from spinning, I have like a 2.3 60'. Any ideas? I plan on getting a 1" drop block for the rear and I work at a machine shop so I will mill it to whatever angle is needed.

Thanks!