Twisted frame?

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I picked up a complete k20 chassis this past spring and am just now getting the time to start my build. After i got it home i noticed a crack that was welded near the rear shock mount. I got a good deal on it so i wasn't too upset about this but i still wanted to use the frame because clean frames are hard to come by in NY. Now that I'm getting ready to tear into the axles, i realized that the frame does not sit right. Im thinking this has to be because of the weld that one of the previous owners made on the passenger side frame rail. The pictures attached aren't the best but you can see how the passenger side frame rail sits lower than the drivers side, and the cross members are slanted at the rear. Is there any way i could fix this and make it usable or is it a lost cause? Thanks for the help guys.

- Also, if more pictures would help i'd be glad to take them.