question about 69 Mustang CJ shaker

First off, my 1st post and I love this forum. Many knowledgeable people willing to help!

I have a 69 Mach 1 with an original 390 with a Performer intake. I also have a complete shaker setup from a 69 CJ car. I assume no problems making this combo work as far as shaker ride height? I might have access to a 427 side oiler later. The 390 and 427 are dimensionally the same, correct? What is the best intake performance-wise for the 427 that will work with the shaker. Many thanks!!