I used the factory harness in the s-10. Pretty much all the plugs were the same for water temp, oil sending unit, etc. I'm not sure about the speedo. What tanny are you going to run 92 trucks had 700r4's and the 95 LT1 had 4L60E's if they were auto's. The 4L60's are computer controlled, shift points, converter lockup, etc. but the 700r4's the converter lockup is the only thing controlled by the computer. The harness I had from Street & Performance just plug up to my factory computer plugs but that was for a speed density set-up on a Tuned Port Injection. Mark or Tony at Street & Performance probably has all the answers though. There is also a fellow by the name of Phil White in Texas that can make a harness for about anything.