On my 71 it is to small for the original filler tube. 70 and 71 there is a lot of things that are different. I can give you ID and OD to check 1 3/8 ID 2 1/4 OD
Learning the hard way. Not all, but most after market parts for these cars are JUNK!! The original part will be the best route. Have a bunch of stuff I bought I never used because it just wasn't quite right. Many dollars later, just spend the money for original, or wait until you can buy it for...