I am sure somewhere in here someone has gone over this, but I am not seeing it. I have an 80 Blazer running 33's with stock suspension, 3.08 gears, 350, and a TH-350 mated to a NP205. I use this mainly as a driver with the weekend off road adventures pretty limited. This truck will be going off road more as I get more done that I want to do. What I need is to find anyone who has been able to correct the speedo using tires this much larger than the stock 235's. Any help would be appreciated.