hello all, i just recently tore out the obd 2 setup out of my 83 z28 and put a high rise intake, new quadrajet, and msd disrtibutor in. got rid of the computer completely and it has been great! except one small thing. the tach isnt reading properly now. before i used to run about 65mph at 2750 rpm. now it says that i am running 65mph at 3500 rpm!! i have read some of the forums on this and it seems like the only thing to do is throw an autometer tach in there but if there is an easier/cheaper fix i would much rather do that considering im a little strapped for cash....any help is much appreciated!!!!