I had received an e-mail from one of the forum members asking if I had any additional information about properly installing a tach in the dash of a '69 Camaro in place of the original fuel gage. In order to make the tach fit properly, after the fuel gage is removed, the cutout in the dash needs to be enlarged for the tach to fit and mount properly. At one time I had a template and instructions for doing this and when the forum member originally requested the info, I couldn't find the template. Well tonight, while looking for something else, I found the template. It is attached here for anyone who might need it.
Tony, hope this is not too late to be helpful with your project. Good luck.