That is good news about the 54 3100 1/2 ton having a 3.90 rear end. I have owned three 50 chevy sedans that all had the 4.11. I am still deciding on which mufflers. I am not a mechanic, so will have to hire all the work done on the exhaust system. Those of you that have removed the old original manifolds, did the bolts holding them on always come out without any trouble? Phil
