im thinking running my dual fuel fairlane on straight gas form now on, what exactly do i have to do? and will it make my gas economy better and is it worth it? thanks

Keep inmind your head gasket, keep your coolant clean, flush every 12months and keep ontop of the cooling system generally, maybe a $70 valve sealer is the way to go for straight gas.

Just a few things, dont touch the timing on the dizzy, get a pro to do it for you as damage can result, maybe get an el cheapo air compressor (if a friend doesnt have one) and blow out your air filter every few months to save replacing it all the time at $30 a pop, get some regular NGK plugs (which have lasted ages for me) and you will be wicked, although some high temp ones designed for lpg would not go astray, maybe replace your leads if they are old and have an impedance higher than 12

Hope that helps
Matt

Hey there again, some more info:
Your air intake and spark plugs and leads are crucial areas when getting power and economy from lpg.
Try adding a cold air intake (CAI), modifying your airbox to allow more-cool air in, see this guys idea http://www.fordmods.com/forums/viewtopic.php?t=56193
Keep inmind, where does the water go, easily overcome and good food for thought.

Intake could use an aftermarket filter, doesnt have to be K&N though, anything washable (high cfm) will give you the best value.
Cheap pods, not great but better then stock and half the price if bought right, will show an improvement.
Keep it clean, if its not washable, wave an air compressor over it every month! Not too close as you can damange the filter material.

Get some high temp plugs and quality sheilded leads, of course you need to balance 'cost' against 'gain'. Replacing plugs and leads that are still 'good' is not a viable idea.

Every few months check the gaps in the plugs, when taking off your plug leads make sure you 'twist' them slightly as relieve alot of pressure on the cable itself (thank you to the gentleman on here who told me that!)

A tune, if required should be performed after all these mods have been done, as lpg requires a tune after any change to your air intake.
You need to keep good fuel / air mixtures, otherwise you can potentially turn your engine into one big giant blob of hot metal.
Depending on your engine and how serious you are about running straight lpg, an oil lubrication system may be a good path for engine longevity. If your game, like me, try water injection!
Keep ontop of all of these and you'll have a great setup.

You have the ability to remove your fuel tank, whether or not its worth it, as you may need petrol one day if lpg is playing up. You can save yourself a bit of weight here, maybe replace it with a smaller tank (10Litres if you can get it?)
Dont run too low on lpg, if you get down to empty you will hear a BANG and your air box, exhaust and maybe some piping will need replacing ($2-300 damage) cut a hole in one of your intake pipes and fit with a tight fit 'plug' that is attached by a string something, so if it does happen, you save your intake as it blows out with the extra pressure!
Hope that helps, thats all i think you will need to know.
Matt