I have a 86 blazer with a rebuilt 305 and a 700r4 with 33 inch tire's and 3.42's. i used to have 35 inch swampers but this summer i lost my second transmission in a matter of 6 months so i had to sell them and get 33's I,m looking into changing the gears out but i don't know what is overall the best performance wise and has the best fuel economy. All know is i don't want to loose another transmission. I do alot of highway driving I cruise at about 75 mph. I think that is the reason i lost my last transmssion was because of all the highway driving i do. When i drive down the freeway it feels like there is a constant strain on the motor. well what I'm asking is what is better overall 4.10 or 4.56. I know some day i will be getting 35's again so should i just plan ahead and get 4.56 or is 4.11 good enough. Also where is the best place to get new gears from and how much does it cost to get them installed. I live in texas does anybody know the going rate down south please help me out "When you say i drive a fullsize are you calling my wife fat." J/K i was bored and made that up i don't even have a wife i'am only 17.