People have been solving that problem for many, many years. For a street type car I use a billet timing cover with the removable center section. That design is easy to set up and easy to adjust and is very rigid. For a race engine I use a Jesel belt drive.
If this is your first big block engine you might want to spend $20 on the book I wrote called "how to build max performance Mopar big blocks". It should answer most or all of your questions.