For the 300 Club: This is what I got back from NGK about plugs for my car. Three spark plug options are shown: GR4, GR4GP & GR4IX with stock number for each. Mark Schueller, 300C,F ----- Original Message ----- From: Info To: f41324@xxxxxxxxxxxxx Sent: Thursday, May 13, 2010 2:58 PM Subject: RE: NGK Form Mail Hello, The factory recommended heat range for this engine is a '4' so the BPR5ES will work but it is one heat range colder than what's recommended for a stock engine. If the engine has higher compression or will be used for racing purposes then you may want to use the colder BPR5ES plug. Regards, Year Make Model Cyl Ltr V-Power Plug V-Power Stock GP-Series Platinum GP-Series Stock IX-Series Iridium IX-Series Stock GAP 1957 CHRYSLER 300 V8 6.4 GR4 2635 GR4GP 2763 GR4IX 7149 .035 Brandon Peeler Technical Support Representative Aftermarket Division NGK Spark Plugs (U.S.A.), INC. 46929 Magellan Dr. Wixom, MI 48393 http://my.artoffast.com/NGKTECH -----Original Message----- From: f41324@xxxxxxxxxxxxx [mailto:f41324@xxxxxxxxxxxxx] Sent: Thursday, May 13, 2010 12:26 PM To: Info Subject: NGK Form Mail **** Contact Form & Tech Info Feedback **** Email From: f41324@xxxxxxxxxxxxx VehicleType: Car Make: Chrysler Model: 300C Year: 1957 Engine Type: 8 cyl hemi Comments: I'm trying to find information about a NGK BPR 5 ES spark plug that comes highly recommended by a Chrysler 300 Club member for my '57 Chrysler 300C convertible. I can't find it on your web site and want to confirm application for my car. Thank you very much, Mark Schueller When: 5/13/2010 12:25:49 PM END OF REPORT [Non-text portions of this message have been removed] ------------------------------------ To send a message to this group, send an email to: Chrysler300@xxxxxxxxxxxxxxx To unsubscribe from this group, send an email to: Chrysler300-unsubscribe@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: Chrysler300-digest@xxxxxxxxxxxxxxx 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/