1970rsr explained to me it has baffles to keep the fuel from sloshing around and easier to add a return line. I already modified my early tank so if I need to massage the return fitting, I will. The fuel fill is not through the hood but I did remove the fender fuel fill just to smooth out the front end. I’ve had a 914 since I was 16 so opening the trunk to fill isn’t a problem for me.