I will start off by saying that I know this topic has been brought up here about a million times. I am doing a ground up restoration on a 1951 five window cab, which is by the way my first project. I have studied the archives and I am still not clear on this question. Most of the time on here I have seen that the patrick's ring and pinion set will give me about ten more MPH. The problem is I have never driven an advance design truck so I don't know what that means. I have seen here and elsewhere that a stock geared AD will go 40 but the pistons are swapping holes. I have also seen that they will run about 50 on top and even 55. Finally Patrick's claims that the with their kit the truck will go 65 without engine strain, which is what I am looking for exactly. So I guess the question in a nut shell is Patrick telling the truth? If the kit only gives you ten more MPH then the truck must run 55 stock? Is this factual? I am going to be running a 235 with fenton headers, dual carbs, dual exhast, and a mallory distributor. I will also be using the tall stock size tires. So I know this is lengthy and has probably already been addressed so I appologize if I missed it. Thank you for any comments!