The 37-62 stovebolt Chevy & 39-59 GMC's had a hole in the bellhousing with a pointer in it. There was a little shiny ball cast into the flywheel which when lined up with said pointer was supposed to be TDC. I'm assuming it's probably a bit off but a good place to start. I don't know whether the marks on the gears line up or not at TDC but the cover is not on so it will be easy enough to see. Thanks for your responses.
