Chevrolet C-10 Fuel Tanks - Nader Approved?

Once you've got the unit nestled in the frame where it's supposed to be (doglegs in the mounting flanges dictate location), grab a couple of C-clamps or quick-release "third-hand"-type clamps (right) to hold in place to ensure the proper fit.

Start drilling with the tank first; that way you can set it back in the frame and use it as a template to drill the 'rails....

...(Also, it's probably best to wear eye protection, especially when drilling from below!)

The welded flanges on the tank go against the underside of the lower framerail lip, so instead of simply using nuts and washers, POL came up with a full-length metal fastener strip to provide more strength. It will need to be bent uniform to the shape of the 'rail and flange.

Obviously, you don't want to bang up your shiny new tank right from the start, so either enlist an extra set of hands or, at the very least, use a stable floor jack when initially positioning the tank between the 'rails.

Once everything fits satisfactorily, pull the tank back out in order to transfer the mounting holes from the fastener strip. As an aid in locating and aligning the holes, grab a pencil or China marker and scribe the inner edge of the framerail on the flange.

It might be a bit tricky to position the fastener strip while threading the bolts in from beneath, as there isn't a whole lot of room to work with, but it's not impossible.

First, verify that the fuel gauge functions properly. To do so, use a couple of jumper wires and tap into the factory sending unit wiring; with the ignition on, operate the float by hand to see if the gauge responds accurately. If not, you'll need to check the gauge itself and/or the wiring harness.

Don't forget to use lock washers on every bolt-that is, unless you're using a different type of fastener, like a button-head with a finish washer, in which case make sure to use plenty of Loctite.