Help with Gas Filler Neck

[blink32]

Been reading the site for a while and now I've got a worthy question.

I've started to replace the aged and cracked rubber gas filler necks. I got new necks, struggled with getting the stock neck off the passenger side tank and now I'm stuck (this is on a 76 dual tanked K10 by the way)

My problem, I can't get the new neck on. Its a 1 3/8" rubber hose with a 90 deg elbow, and I checked the stock one I removed and it was also a 1 3/8". But the Metal gas filler lead that it connects to is about 1 1/2" or so. But there's an additional hump or lip that makes it like 1 5/8" or something. I've tried everything I can think of, heat the hose with a heat gun and try to jam it over, lube the neck and hose with grease, freeze the neck and boil the hose. But its just not working. The best I've managed to accomplish is to get the tube wrapped over the initial start of the metal pipe before the lip. But I can never get it past that. Is there some other trick or tool that I can use to stretch this hose or am I just not trying hard enough with the current methods? I really need to fix these. Thanks for any help.