I offer this advice because 6 months ago, my 245 wagon developed a gas smell seemingly out of nowhere.

My hunch: Does is smell like it's coming from the ventilation system when you drive? Where the AC comes out in the middle of the dash?

First, with the car running, or as soon as you smell the gas, pull over. Leave the car running. Open the hood and look for the fuel pressure regulator. Here's a link to a photo of a 240 engine

http://www.240glt.com/megasquirt/8.jpg

You are looking pretty much smack in the middle of that picture for the Fuel Pressure Regulator. Has a black tube running out of it. Top of your engine, about the size of a small 8oz can of tomato paste. My hunch is that with the car running, you will see this "wet" and leaking fuel. The diaphram inside of it goes.
About $45 bucks. Get the Bosch made one if you can. 5 minute fix with a screw driver and wrench.

Looking at this after the car is off might not show you the leak, as the fuel will evaporate very quickly with the engine hot. With it running, you will see it leaking if it's the problem. Replace it immediately if that's the case.
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89 245 'loaded' with a Great Pyrenees