My C20 has idiot lights and I would like to install gauges. There is a truck at the local wreckers with a gauge package. Do I have to change the sensors/sending units also? This is a 350 engine and I am looking at oil pressure, water temp and voltage.
Yes, the sending units are different for gauges. I don't know if your oil pressure gauge will be mechanical or electrical - the original one in my '75 was mechanical, an oil line ran from the engine into the dash just like an aftermarket gauge. Later trucks had the electrical oil pressure gauge, not sure when the changeover was made.
I'm also not 100% sure how the voltmeter will hook up, you will need the entire dash "guts" from the donor truck. What year is the donor? Although identical at a glance, seems like every couple of years enough subtle changes crept in to make the instrument cluster circuit boards not quite interchangable, which I found out when looking through the pile of ones I'd saved when I had to replace one.............................
It would be far less trouble to just install a set of Auto Meter gages.
Not to mention that they look far better than the stock ones.
I have temp and oil, an Ispro voltmeter. and an inside outside
temp gage in my dash.
It took me about 3 hrs to install.