The only couple of old clear Polycarbonate casings I have were butchered to fit larger motors that had no place ever being fitted to a Gen8! 
The standard Nylon cages can be fettled to work on the Singularity Gearboxes⌠but thatâs just more work and mucking around if not needed by fitting a clear case from the beginning. 
Iâll have a dig around, but I already know that most of those old polycarbonate parts got sent to Gelblaster heaven where they belonged!
T piece question.
Iâm going to put in a new tpiece, as the old one has a crappy seal / loose barrel.
I tried a fit of the barrel, in the new t piece.
It doesnât wanna go in.
Looking closely, the new tpiece has a different internal lining material.
Do you need to âboil the barrel in.?â
I.e. heat it soften in, then itâll push in and harden around it.?
Do you then apply a bit of araldite around the outside, to complete it?
I seem to remember talk of thatâŚ
Iâve never heard of having to heat up a t piece to soften it up for fitment. 
If a barrelâs too tight to fit I usually measure everything up then either carefully run a 9.5mm drill into the t piece or reduce the OD of the barrel at the grooved end.
I was able to reuse the old tpiece anyway.
Now araldited in.
I might try the hot water thing, anyway just to satisfy my curiosityâŚ
The hot water trick usually works on plastic barrel removal because the clear barrelâs made of different plastic to the ABS plastic used on the t piece and softens more easily with heat. Why you can stretch it out of the t piece and break the glue bond. 
Think youâll find heating the t piece up in boiling water wonât soften it much, although leaving it in long enough will definitely screw it up. Ask me how I know. 
But do the science, by all means.
Well 10 second quarters will do that
Think you are getting confused to soften the glue works not to expand things.
Had to do it the other day not blaster but work stuff