Installing front sub frame rail

Plus if the existing K frame is bent, you wont know it. It would suck to line up the replacement frame rail with a tweaked K frame, then you end up with a bastard that no other K frames will fit except for your bent one. I would use any 67-76 K frame either V8 or slant 6 that's known to be straight as a jig to install this framerail. Then if your original K doesnt line up after that, you will know yours is indeed bent. At that point go looking for a replacement K frame.