Big block in Dart: transmission fill tube issue- tried everything! Help!!!

We have jimmy rigged the wrong fill tube for the tranny on their temporarily 2 years ago, it leaks out the bottom and is the wrong size and measurement...

The correct size doesnt fit because of the heater box and everything right there is in the way...

We tried a flexible tube but it won't sit at the right angle...

Anyone familiar with this issue? Anyone know the fix??? I have tried a tube for a big block dart, a different one, and a flexible one... Help!!!
I HAD TO GO TO FLEXABLE TUBES ON MY TRANNY AND ENGINE BOTH. THE RIGHT ONES WILL WORK IF U CAN FIND THEM. FILLING THRU THE NEW TRANS FLEXABLE TUBE IS A LITTLE BIT OF A HASSLE , BUT HOW MANY TIMES U GONNA FILL IT AFTER U GET IT RIGHT?. YOUR DART IS NO SMALLER THAN MY 68 FASTBACK.--dam, I cant stay of the caps button !