I checked my carfax thanks to Shawn... and.... it says i have a 305! Its an 87, were 305's even an option or a standard that yr?? how do i tell if its a 350 or 305..... i dont have a hand booklet thing... Hrmm if it is a 305 that would account for the slowness... if its not a 305 then my tiny gears prolly making it slow. 6in 87' K5 w/ 35" BFG muds. Kn filter What I need: 4.11 gears, Lim Slip Dif, Force2 Catback, rear springs , Throtle body spacer.