I'm doing a similar swap (T5 behind a 250). What I found is that the Camaro bellhousing will bolt up to the 250 block, but won't clear the flywheel. The Camaro flywheel won't fit the 6-cyl crankshaft, so I had to use a 6-cyl bellhousing. The one I'm using is a cast-iron one with mounts on the bellhousing (casting #3815891). My local GM dealer tells me it was used in 75 to 93 light trucks.
Which brings me to my current problem: I need the clip that holds the clutch release fork to the ball stud. It's a wire clip that looks like the Greek letter omega. My dealer tells me the part # is 403051, but GM doesn't sell it. Apparently, it's not expensive enough for anyone else to bother reproducing it either.
Does anyone know of a substitute (snap ring, e-clip, etc) or is this a generic part that's readily available if I just knew what to call it?