hey all, this pertains to a car I'm building, but I figured the 10 bolt truck/car setups were the same. To run 4.10's in a 8.5" 10 bolt that originally has 2.40 gears, all I'll need is the $30 spacer from Summit made by Mr. Gasket and a new ring and pinion correct? Will the spacer only allow me to run 3 series gears in a 2 series carrier, or will it let me run 3 series OR 4 series? Maybe I'm stuck with 3.90's in other words? Is it that simple or will I need any other parts I'm not aware of? Thanks!