I have an oppertunity to get a 86 305 from an 86 chevy van (45K) for 200 bucks. I have an 85 K5 with a 305. Any problems swaping out? The one I have now is definitely in need of a valve job and the vehicle is simply a daily driver. Also, rear axle seal is leaking. It has a standard 10 bolt. Am I looking at a major undertaking to replace this seal?