Hola ( _______ ) At first I was going to send my reply direct to your email. Then I realized that some do not know what the option of manifolds are. Soooo. Since you came in on the 1966 subject, I am going to guess that you have this style of vehicle. The 1961 to 1966 exhaust manifolds are the same on the drivers and passenger sides of the car due to the location of the starter, steering clunck and frame. The passenger side will accept also until the last Imperial was made. But if you do this your exhaust system will not be even. The driver's side only has room for Imperial exhaust parts. No Crashlier parts or the such on this side. But, there is even up-dated performance availiable, ... if that is what you want. The 1972-1978 400 or 440 cubed motor in any Dodge truck has a pair of manifolds that fit the 1961-1966 Imperials (http://cgi.ebay.com/1975-75-DODGE-RAM-PICKUP-400-440-Exhaust-Manifold-NEW_W0QQitemZ8065345750QQcategoryZ33632QQssP ageNameZWDVWQQrdZ1QQcmdZViewItem ) or you can use a company that is called A-1 from Ariz that also sells new manifolds. As you can see they are the next generation with-in the top part and they have a longer lower portion. If you by one from what ever source, you must use two. Now to what I think is your problem. Change your valve cover gasket. Rodger & Gabby Colo Spgs '47 De Soto Custom w/Fluid Drive & passenger door mounted swamp cooler '62 Crown Coupe w/std A/C & Auto-Pilot '66 Le Baron w/dual A/C & reverbed AM/FM '70 Overlander - InterNational Dbl '70 W100 w/318, NP 4 Spd, 3:55 & Short Box '77 D150 w/360, NP 4 Spd, 12 Bolt Axle, OEM Buckets & etc ----------------- http://www.imperialclub.com ----------------- This message was sent to you by the Imperial Mailing List. Please reply to mailing-list@xxxxxxxxxxxxxxxx and your response will be shared with everyone. Private messages (and attachments) for the Administrators should be sent to webmaster@xxxxxxxxxxxxxxxx To UN-SUBSCRIBE, go to http://imperialclub.com/unsubscribe.htm