There were so many rules and restrictions I decided to have the installation done by a professional. The timing had to be adjusted (needs to be retarded for LPG). We also installed a Pertronix Ignitor and Flamethrower coil. We also had to use colder spark plugs because LPG burns at a higher temperature than petrol does. It also burns much cleaner. It will actually 'clean' carbon deposits in cylinder heads and the oil takes a lot longer to blacken. On the downside mpg and compression (and thus oomph) drop slightly but I haven't been able to tell the difference.
This is the most noticeable change under the hood. It serves to evaporate the pressurized LPG using heat from the cooling system. Not pretty to look at but nothing permanent either (should petrol prices magically drop).

Most American classics here in Holland run on LPG. The IMPCO installation is probably most used for this. However, these won't fit my Continental because the hood won't be able to close. So we opted for this (very old school) ring that sits in the air filter on top of the carb. This way I get to keep my air filter & won't have to cut into the frame of the hood. Some material still had to be removed from the carb and the ring had to be changed in some respects also.

Two 55 litre LPG tanks in the trunk:

The LPG system has been maintenance free so far. The car starts up immediately. On the high way doing 60 the MPG is just under 17. In a residential area mpg drops to around 8.2 There are so many speed bumps, roundabouts and traffic lights in Holland you won't believe it.
Here's a little arithmetic i did in February 2008.
Petrol is $10 a gallon in Holland.
If you I had to fill up with petrol, I'd pay $242.21(USD)
That's why I had mine converted to run on LPG. Filling it up costs $72.55 (USD)
That's a $169.66 difference.
Petrol:
24 gallons/109.08 liters X 1,515 euros a litre = 165,26 euros ($242.21)
1 Euro (EUR) = 1.47 US Dollars (USD)
LPG:
19.8 gallons/90 liters x 0.55 euros a liter = 49.50 euros ($72.55)
1 Euro (EUR) = 1.47 US Dollars (USD)
Now of course my '64 didn't come with an LPG system installed. It cost me $1500 euros or $2198.40 to have it installed. Still, I break even after 12.95 fill ups. In case you're wondering; a car that runs on LPG has a more expensive road tax. LPG is therefore economically interesting if you drive 12500 miles or more a year. Cars over 25 years are exempt of road tax
