When I installed my engine years ago I cut the heads off bolts and slotted the ends. Then I used these as guide pins to align the trans to the bellhousing. Once aligned I replaced the guide pins one at a time with bolts and tightened them equally to draw the tranny to the bellhousing.
I do exactly the same thing and it works really well. I use that method on anything that's heavy and awkward like tractor final drives and such and it makes the job much easier.
