Unless you've done this before, I urge you to consider the modifications you'll have to make to your base 440 to make it capable of accepting the six-pack intake. Here's a link to a quick overview of the changes to top and bottom
http://specifications.homestead.com/6pak6bbl.html
Should you decide to go that route, you must also consider whether the Imperial's drive train, suspension and wheels are adequate for the engine. Last, but not least, there's the noise factor. The 440 you have is appropriate for a quiet cruiser and has quietness built in.
IMHO, you may want to consider putting an Imperial interior into a Superbee to accomplish the same objective. Probably easier than what you're proposing.
Just kidding about the Superbee. There are some street mods you can make to bring up your base 440's horsepower by 50 or 60 without ruining the Imperial "feel". If you don't already have dual exhaust, do that, and you can consider headers as well. Get an H-crossover pipe installed, X if you have room, and watch the bottom clearance. That would be a custom exhaust job, and you'll pay a lot for it. A cam with longer duration and better lift will help, as will properly a properly ported stock 4BBL intake manifold. At a minimum, get a Suregrip rear end if you don't already have one. With those mild mods you will have a 400hp sleeper without changing the Imperialness of it all.
I recommend you seek the advice of a local speed shop and stick with street mods, not street/race or race only. In the long run, I predict you'll spend less money and you'll be happier than if you go the six-pack route. Not only that, but you will be able to sell the car if you ever decide to do so. There are a lot of people in the club who shy away from any Imperial that looks like it's been hotrodded.
Back to the Home of the Forward Look Network