Right now i have a 267 w/ th350, GM 7.5 rear with 3.90 or 3.93 not sure. I don't know thats what the guy told me, Its a daily driver/ Street project. Up coming shortly will either be a 350 or a 327 w/ double hump heads. Keeping the th350 trans in for awhile yet. Wanting to know what are my options for a new rear end. I'm the type of guy that will spend the money to do it once and be done. although im only 18, but i got it. Ive heard of doing the 8.5 GN rears, 12 bolts, and ford 9 inch. personally id rather do the 8.5 or 12 bolt chevy, unless a ford 9 inch would be the same amount of work for a better rear. Does the 8.5 make a clean swap? Does the 12 bolt need modifications for suspension? Is it just shortening if the drive shaft/ New longer one ordered? I need all the info about the rear end, work involved, what needs to be done to have everything tip top shape to make the best decision. Any advice on an engine would be helpful too. Whatever knowledge you guys have is beneficial. THANK YOU!