I have recently purchased 2 oil tank filters 29-7962 from different suppliers neither of which seem to fit the oil tank of my 1970 Starfire. The thread on the replacements is 20 TPI just like the original. However the diameters are 0.864" as opposed to 0.875" of the original (7/8"). Has anyone come across this before? Are there some of dodgy manufacture out there?