I have a friend that has had thoughts of putting a Toyota 22R in a 64 Valiant. He is a Mopar guy for the most part but for some reason he thinks that this is a viable swap. My contention mirrors what others have noted here.... The resultant LACK of torque coupled with the 2800+ weight would make for a S L O W vehicle which would get mediocre mileage. A well tuned slant six with a 2.76 gear can get mid to high 20s mpg. The Feather Duster and Dart Lite were EPA rated at 36 MPG in 1974, and those cars were a shade under 3000 lbs.