Looking for a 250 inline 6 in TX/OK/LA

[2bits]

Hey guys, I put a 250 in my truck and it is giving me serious grief, and not going into the issues, if I can come across another one that runs good, I would consider just swapping it out. I am looking for one with a NON- integral head that doesn't smoke, knock etc. I want something I can put in and drive. I have a new Carb, dist, etc so if those are bad that's ok. I want to stick with a 250 just due to the brackets since I have all the accessories already installed on mine (292's are different etc) and I want to swap it out in a day without any additional conversion. I can come get it up to a couple hundred miles.