What is the best way to get the proper pinion angle on my 71 chevelle that now has an ls1 with 6spd? All suspension is currently stock. The differential is pointing down 3 degrees and the drive shaft is pointing down 10 degrees. My transmission tail shaft is 10 " higher than my yoke on differential. Based on this information I calc. my current pinion angle as -3+(-10)=-13 and i have read i should shoot for -3. I'm thinking I should lower rear of trans and buy adjustible upper arms and lengthen them out to make rear end angle near 0. Am I heading in the right direction? Any thoughts?

If you lower the rear of the trans you will increase your drive train angle further. If it goes down - from -10 to say -13 and you raise the pinion to zero...your still at a -13 drive train angle. I would think you would want to raise your tail shaft to reduce that angle. The easiest way to change the pinion angle is with the adjustable uppers. I have also read about a method of elongating the mounting holes of the stock uppers then welding washers in place to obtain the correct angle.

This site (http://www.5speedtransmissions.com) has a lot of good info on drive line angles

thanks