There is NO WAY that you can even put an xtreme on this as the top of the carb is nearly even with the top of the flow surface on the inside of the air cleaner base.
If I put even a filter 1/2" taller, it hits the shaker when mounted.
Running the orange filter (4") on this car and NO shaker - it is like another car. The low rise filter/lid/base is holding it back.
You SD guys must have gotten a different shaker/base from the factor. I am pretty sure this is the original 76 stuff. Yeah, the 76 455 was rated at 200hp. I think this is one of the reasons why.
I APPRECIATE the help. PY's picture deal is broken, so I put some pics on the zone site: link
http://www.pontiaczone.com/forum/showthread.php?t=21864