Hi Larry and All: Here is the best I can do to answer your question. According to a chart from Chrysler engineering ("K" -- Muffler Specifications) that I have, there are NO mufflers for any model as short as 9.5 inches in 1957. The closest spec to the 300C convert listed is the C76 (New Yorker Conv. Coupe). For it, the front muffler is 15 inches long and the rear 12 inches. Strangely, the 300C CC is not listed. I would see no reason why the muffler LENGTHS would be different, though. The D500 coupe and convertible are both listed, and the convertible front muffler is also 15 inches and the rear 12. The parts book is not any more help on the 300C, as it just says "except Convert. Coupe". When one looks for this elusive CC, it is missing. The AMA specs are even less help. So, Larry, All I can say for sure is that Engineering listed no 9.5 inch long muffler for 1957, and when they did show a performance convertible (D500), its front muffler was the same length as the NewYorker convert. In fact, All convertible carlines except Imperial have a 15 inch long front muffler and a 12 inch long rear. Soooo, I would say the circumstantial evidence is strong that the 9.5ers are the wrong length. Glad the system sounds great, though!! 300ly, Gil Cunningham Cool Tallahasse, FL In a message dated 5/15/2008 8:38:50 PM Eastern Daylight Time, JettLarry@xxxxxxx writes: Several weeks ago I queried the gang about four mufflers for the 57 C rag. The only name brought to the thread was that of Waldron. I ordered the four quieters from them and took them to Midas for fitment. They said: "There aren't the same as on your car. The rears seem to be real close but the fronts are much smaller than what you have now" Sure enough, the two front flow-throughs were but 9.5 inches long, several inches shorter that the previous. Then I remembered that I got the first set from Keplich so who knows what they sent me. I had the guys work out the shortages with front-loaded extensions and the new system sounds REAL nice and solid. Graefin's remarkable book on the C restoration doesn't tell the length of the front mufflers. Any chance that they should have been 9.5 inches long? L. Jett, where it is 102 degrees today in Newark by the Bay. Waiting to go to Reno to cool off.... **************Wondering what's for Dinner Tonight? Get new twists on family favorites at AOL Food. (http://food.aol.com/dinner-tonight?NCID=aolfod00030000000001) [Non-text portions of this message have been removed] ------------------------------------ To send a message to this group, send an email to: Chrysler300@xxxxxxxxxxxxxxx For list server instructions, go to http://www.chrysler300club.com/yahoolist/inst.htm For archives go to http://www.forwardlook.net/300-archive/Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Chrysler300/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/Chrysler300/join (Yahoo! ID required) <*> To change settings via email: mailto:Chrysler300-digest@xxxxxxxxxxxxxxx mailto:Chrysler300-fullfeatured@xxxxxxxxxxxxxxx <*> To unsubscribe from this group, send an email to: Chrysler300-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/