Siezed 273v/8

I have a 1964 valiant siget 200 2dr. It was running when it was parked inside for about 15 years I live in British Columbia Canada . We are trying to get it to turn over and some members have recommended using marvel mystery oil to help free it up . We will be taking the heads off after christmas. My problem is that they do not ship . marvel mystery oil to canada anymore .So i am looking for info from members in Washington State[ 1] - if it is still available and [2] -Which store can i buy it . With this info i can plan a road trip . Any help would be welcome . thanks in advance for your time and help in this matter al cronk valiant64
Author: valiant64