A Couple Gauge Questions.

[Scootin 81 C20]

I have a couple of gauge questions for you guys. First, I'll start with what I've got.

The guages are all original, as far as I know.
The engine is a GM crate 350 with an HEI distributor.
The truck is equipped with dual tanks.

Ok, now for my questions.

My fuel gauge reads just past 1/4 of a tank when the passenger tank is full. My driverside tank leaks, so I don't use it. Why is my gauge reading like this? It reads as it should when it gets down to 1/4 tank on down to empty.

My speedometer bounces while driving, even on a smooth road. Also, when I stop and shut the truck off, the speedometer doesn't go all the way down to zero, it sticks around 10 to 15mph when it's off. Why is it, or What is it that's causing this?

Ok, my final question. Like I mentioned above, my engine has an HEI distributor on it and I'm wanting to put an old school generic tach in it. My dad and I are uncertain about how to hook it up with the HEI? My dad has hooked up tachs for points style distributors, but not HEI.

Any help is appreciated.

Thanks
Benjamin.

[Unofficial]

The only thing I can contribute to your problems is the tachometer question. I have a 350 with an HEI distributor also, and I recently hooked up a tach. The only thing that hooked up outside of the cab was the ground and a wire that hooked up to the negative side of the coil. I'm not sure how much that will help you...

[Prong]

I can help on two of your issues:
The tach lead plugs into a tach terminal on the cap next to where the 12v lead attaches. On the speedo bouncing, disconnect the cable and pull out the inner cable and lube it using white lithium grease and that should cure the bouncing needle issue.