I'll have to pull the hub back out and will post pics and dimensions. The shoulder is in the middle of the bearing with steps down to the nominal 33mm race size in front and back, so that probably wouldn't work just from eyeballing it. This is another area where GM really screwed the pooch on design - all in the name of saving a quarter of an inch.
The hub is a relatively loose press fit to the shaft and I believe even OE used threadlocker to secure it once aligned to TDC. It's fairly easy to remove by holding the hub with something and tapping the shaft out with a punch - no vise or pullers required. Most of the rebuilders drill a 3/32 hole for a roll pin at the mating line before disassembly so they don't have to re-index the hub. I don't want to attempt to remove the hub from the bearing without a replacement bearing, so that will be at the very bottom of my bucket list.
I'm not feeling like messing around in the garage any more tonight - just finished the 44th oil change (x 10,000 mile interval) and tire rotation on my daily driver, removed the trigger wheel to return the junk distributor base for a refund, and washed the sooty smelling oil off my hands. Going to spend some time relaxing and entertaining my daughter's dog that she swore up and down she was going to take care of. The animal would fetch the tennis ball from 6am to midnight if there was someone willing to throw the damned thing that long.
The results I had with the other trigger wheel seem to show the a similar pattern of timing skew, trending towards +3 degrees between cyls 1 and 8 and zero around cyl 6. The only explanation I can think of for this other than a junk trigger wheel is that my cam gear is slightly elliptical. Without others reproducing this test on different engines I don't really feel alarmed enough to warrant pulling the timing cover and possibly creating a new oil leak. For all we know at this point, a brand new OE timing set might produce more erratic results. And though we're geographically diverse beyond the pale of vision, I don't see a line forming of LT-1 owners wanting to yank their water pumps to attach a degree wheel and find true mechanical TDC to verify. Ultimately my intentions were to upgrade to an electric water pump so I can run a standard double roller timing set, so maybe that will be my excuse to pull the engine next winter.
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