I have an open drive 3:54 ring gear and pinion that I want to put in a 39 ford banjo rear. I have never done any type of rear end work and never switched the R&P before. I have read a few tech write ups on here but just dont feel confortable doing it. So I called a shop who does rear end work and they priced switching the R&P for me and it would be around $250. Does that sound reasonable?