I don't know about any system on the big blocks, but on my '83 I was told to keep it. It supposedly does not use more than 3 or so hp. If you take it off I hear they components rust/deteriorate rather quickly and the tubes run into the heads and can cause a leak. On the other hand my cousin used to rip them off his VWs immediately Rob _________________________________________________________________ Join the world�s largest e-mail service with MSN Hotmail. http://www.hotmail.com