A couple of A-body rookie questions.

I do still want to know if I have to mod the tunnel to put a 727 in it though.
Yes you do, but then it would be the same mod with a 10.5 clutch as a 727. I had to fold the lip over on mine where the floor meets the firewall but no big deal.
Early A body cars came with a smaller bell housing with a smaller clutch for the small trans tunnel for your info.