I have an Lt1, but it came with the 2.73 gears and had the 1st gear blocked. Well i've fixed all the, but my speedo guage only goes to like 115 mph or something like that. I want to put the 155mph guages on, but how will i get the pcm to read it as the 155 and not the 115 one? Any thoughts or knowledge is appreciated. Thanks

 

The PCM doesn't care which speedo you have.... it sends the same signal, and the speedo responds to it if it can (e.g. - go to 155MPH). All you need to do is swap in a 155MPH cluster and you will be fine.