Here is my totally reversible way of mounting the shaker to the hood. This setup is designed to be used WITH an open scoop for cold, fresh air intake.
I simply used a piece of aluminum channel for a support along the backside, a small angle bracket to hold the front up, and siliconed with GE Black silicone all the way around to make it water-resistant.
*This is TOTALLY reversible as well. All holes I used were existing in the hood channels. The silicone peels off cleanly as well. I've had the shaker on the 77 this way for probably 20 years. Took it down a year ago to touch it up and the silicone came off nicely and re-mounted it the same way.
I also use some foam peel-and-stick weatherstripping around the scoop (layered as necessary for flush mounting) to get the shaker nice and level.
Hope this helps!
And for an aircleaner, just run any aircleaner that fits inside the scoop. In the 77 I run a customized version of the triangular aircleaner nobody likes, but without a filter as it is a summer-only (non dusty road) car. My 80 has a 10" chrome round aircleaner, as it sits outside many times in the rain. This way, water doesn't run into the carb when sitting.
The nice thing with this setup is you can pull more air in if you get either a carb and/or aircleaner spacer (done right it is a pseudo-Ram Air effect). The added height tucks the aircleaner into the open scoop and allows more forced cold air to enter the carb = more hp!