I tried the telescoping rod trick on both my friends and my car, and there is no way the stock air cleaner will fit. It might with a 2" drop base, but those are too small in diameter to fit the factory air cleaner, and will leave a large gap on the bottom.
I have a 3/8" thick heat reducing spacer on top of my 'Performer' manifold, and the rod trick showed that I have just over a 1/4" clearance between the top of my dual snorkel air cleaner and the hood (in fact, when I had a broken left motor mount the left snorket was rubbing on the hood).