Hey Richie-the mid to late '70's Camaro/Firebird is supposed to be a winner for these trucks, apparently. Very nearly the correct width. What you need is careful welding in alternating spots, from one side spring perch to the other to minimize warpage. This of course is AFTER you determine your pinion angle. Measure this using an angle finder, first laid flat against the end of your transmission output shaft. Then, you lay it flat against the pinion yoke, 180 degrees opposite to the output shaft. Example-if your transmission output shaft points 3 degrees DOWN from vertical, your pinion flange must point 3 degrees UP. Getting these angles right is VERY IMPORTANT-you could buid in driveline vibration if you don't! Also, you may have to fiddle a bit with the leaf spring locating hole in the spring perches-the stock rear axles weren't centered in the wheel openings. I hope this helps you out a bit.
Wannabe
