well it's been a decade now, but I think I got them at the auto parts store. make sure they are grade 5 or better. and don't forget that you'll want them a bit longer than the original bolt (both because they thread further into the hole than the original and that you'll need a bit of thread to stick out for the nut to thread on). once you have the trans out you can easily thread one of the originals back in to see how deep it goes, and then add that measurement plus the thickness of the bellhousing plus an inch for the nut.