US cars are one of two sizes; can't say what happened where you are. Through 1972, GTVs and Berlinas used the bayonet style common to 1600/1750/early 2000. Then in 72/73, in the US, they went to a threaded cap like on Spiders. Then in 74, back to the bayonet again. I don't have the numbers in front of me on size though.