[Scarebird]

We are planning a move to Portugal next Fall. To my wife's chagrin I plan to take my 71 Lemans with us. One of the many minor issues is license plate size. The normal EU size is 20" x 4.3", not a good fit.

Are there other sizes? I sometimes see more rectangular variants.

Also, given we will remain US citizens and the car has permanent Washington state plates, will we need to change?

[OG68]

Be sure to download and copy the AMA specifications for the LeMans. I helped a fellow in Malta obtain the information the authorities required to register his 68 GTO. Most of it was in the AMA specs that PHS supplied.
Not sure whether that applies to Portugal or not but it may be good to have.

[Scarebird]

I would not be surprised if they did.

Hoping the Washington plate thing is an ace up the sleeve...

[Charlie Brengun]

Portugal, you picked a lovely country to live but a horrible language to learn, rather difficult.

The license plate sizes allowed will be country specific. I don't have a clue what is allowed in PT or not. However what you can do is find some Portuguese car sites (PT version of ebay for example) and start looking for pontiacs, dodge rams etc , US car and see if they have the smaller plates on them. If it's fairly common, there is probably a way to drive around with them legally.

For keeping the car on US plates.
How are you going to insure the car? Using a US based insurance company that has European coverage? As it may prove rather difficult to find an insurance company that is willing to insure a car that does not have a Portuguese registration.
In my country, you can drive a car with foreign registration plates but you will need to maintain a valid US drivers license and when stopped claim you are just on an extended visit and brought your car and are actually still living in the US if asked about it.
Of course if you ever have a serious accident this may come to light and cause problems.

If you move to NL I can tell you exactly what is and isn't allowed here but I'd also pick Portugal over NL myself if ever given the choice.

[Scarebird]

I agree, Portuguese is tough to learn.

I will try your idea of .pt ebay and see what shows up.