anyone know if a 280 coupe gas tank will fit in an early model 260?

Not absolutely sure, but I think if you use the straps from the 280 tank it will work. The 280 tanks are a bit larger by about a gallon. Perhaps someone else has done this and can give you an accurate answer.

I know a guy that's got a 76 280z tank on a 240z and one of the things he had to do was get bigger straps to hold the tank up, so I'm pretty sure it will work with minor moding.

I have a 240z with a 76 280z tank. The only thing I had to modify was the straps. Made one side longer. Cost me $10 to make it longer.

My friend who has a 260z was able to use his straps basically he didn't have to do any mods.

Others say they had to use the 280z straps or make there 240z straps longer and some of them said they had to put a longer gas intake house. Almost forgot, just cap your extra hoses.

Right on, thanks alot guys!