The pinion angle can be adjusted by using a tapered shim between the spring perch and the spring. Most driveline shops or places that do heavy truck repair should have something that can be adapted to work. Be sure the weight of the vehicle is on the springs while you're checking the driveshaft angle, or you're likely to encounter problems with the angle changing once everything is in the running position with the wheels on the ground. If it's really way off, the only option is to cut and reweld, but you need to check everything out with things assembled before you start modifying again. Pinion angle problems will cause oddball vibrations, and short universal joint life unless they're corrected. Next time, clamp everything together before you weld, and mark the housing for the correct fit, then disassemble it and weld the spring perches to your marks.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
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