Smitty Here is the number one item to lookat on your heads. The valve cover retaining bolts/ studs. Do you have four ? If you do, then, this means you have the most likely the original heads. But MoPar or any one else did not like these heads. From the marine division of MoPar they had a head which had six attaching points to hold on that leaking valve cover. The marine head also flowed better air than the first series head that you have on your 413 powered Imperial ( or 383 powered whatever ). The casting number of the last and best flowing heads for the big block MoPar engine is number 4006452. If you find a set of thes heads the rocker arm assembly needs to be kept with the heads for the first series rockers will not fit anything except the first series. 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 '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