Got more luck than most, never had a v4l carto fit on any 510 without an adapter..
Ya can get a 510 to 901 adapter that will work great though.. there around $3 at most places..
EDIT: oops misread lol..didn't see title..
I got my adapter from americaneliquidstore and all the v4l cartos I bought and the samples I got from them worked on it everytime.. maybe some adapters are made different, I don't know..