I have an 89 GMC Jimmy with a 350/4 speed to 10 bolts front and rear. I am also running 35" tires. I am in Louisiana so all the off road is mud. I am thinking about upgrading to a 14 or 12 bolt. I have 2 questions: What gear ratio does everyone recommend? If I went to a 12 or 14 bolt, what years would match mine? Also, are truck rear ends the same as for Blazer/Jimmy? I have never done an axle swap so I am wondering what will bolt up easily. Thanks for any feedback in advance.