I don't know what is "normal" for a sbc but the one I had in my 23 idled at 45 and got up to 70 going down the road. One thing you might have is a mismatch between the sender and gauge. Gauges require a certain ohm rating on the sender, like 90-270 or something similar. If the sender is not what the gauge wants to see the readings will be off. Stick the mechanical one in there and test it, then you will know.


Don