Hi Dan & all, I can tell you that my 390hp 300C has a rivet/pin attached to the front edge of the cylinder head where a tag may of been attached signifying the higher compression/part number for the 390hp cars. This car also runs a special intake with no exhaust cross-over passage. I also have some information on Kiekhaefer's 1952 and '53 testing of the 331 hemi for the Mexican Road Race. Kiekhaefer's dyno firstly revealed that stock factory hp rating of 180 was on the conservative side. After tuning and conditioning towards high speed road racing, with no radical changes, Kiekhaefer got an increase of 30% at the rear wheels! Much of the work/experimenting carried out was on the exhaust system. On the '53 NYer Special Road Race cars he settled on a 3 1/2 inch dia pipe just long enough to reach the LEADING edge of the front door. The Bettenhausen '53 NYer was clocked in at better than 142mph and they had faster straight line speed than the Ferraris competing in the race. I believe that on my 390hp 300C and probably the 355hp 300B as well more hp was gained from the "free flow" exhaust system than the change in cylinder heads. My 2 bits worth. Owen Auckland,NZ -----Original Message----- From: Chrysler300@xxxxxxxxxxxxxxx [mailto:Chrysler300@xxxxxxxxxxxxxxx] On Behalf Of Dan Elliott Sent: Wednesday, 7 May 2008 3:19 a.m. To: Rich Barber; Chrysler300@xxxxxxxxxxxxxxx Cc: us@xxxxxxxxxx Subject: RE: [Chrysler300] 1955 AMA Specs (Last update?) Rich, I certainly believe that the AMA specs would have been updated for the 1955 300 at least once, to add the three speed manual transmission used in NASCAR starting about April 1. Then there would have been a NASCAR bulletin approving the use of the manual trans. I just returned from NASCAR archives, they don't have alot of that info publically available, so one needs to go to private sources. On a slightly different question, it would be interested to know if the 355 HP heads had any markings on them that are different than the 340 heads. My guess is "NO", but one never can tell. The part numbers were different of course, but no 300B ever came down the assembly line with 355 HP heads because the last 300B was built and shipped before Chrysler dealers were notified that the optional heads were available. An unanswered question is whether the 355 HP heads were used in NASCAR, to date no photos have appeared showing a car in actual competition with 355HP painted on the hood, a NASCAR requirement after it approved the use of the heads. Photos at ElkHart Lake in August, and Darlington in September both show cars with 340HP. Carl K. could have snuck them in, unless he won with the subsequent teardown, so I'm assuming he didn't. He did sneak in higher octane gas, which may have been his thinking with the 355 HP heads. But perhaps by the time they were approved by NASCAR in mid June, someone had gotten onto his trick with the gas, and he couldn't use it anymore. He certainly didn't want any disqualifications, because Buck Baker was behind Herb Thomas during mid season, until the infamous crash at the Shelby fairgrounds. So if the 355HP heads were used at all, perhaps it was after mid September, 1956. Dan Elliott -----Original Message----- From: Chrysler300@xxxxxxxxxxxxxxx [mailto:Chrysler300@xxxxxxxxxxxxxxx]On Behalf Of Rich Barber Sent: Tuesday, May 06, 2008 12:10 AM To: Chrysler300@xxxxxxxxxxxxxxx Subject: [Chrysler300] 1955 AMA Specs (Last update?) I have been able to obtain a copy of the 1955 AMA Chrysler specs with the 2-15-55 updated sheets that added the 1955 Chrysler C-300 on that date. I find it interesting to note the similarities and differences in the Windsor, New Yorker and C-300. Imperials are not included. I think they were considered to be a separate brand at that time. I had been asking about exhaust and tail pipe diameters and find they are the same for the '55 NY and C-300. 2" exhaust and 1.8" tailpipe. It is not clear as to whether these are OD or ID, but I guess muffler shop guys would know. I plan to go with 2" and 1-3/4" if those are the standard nominal sizes. I would appreciate hearing from anyone that has another set of 1955 Chrysler AMA specs as to whether their set shows any further changes were made to the specs after 2-15-55 during the year. I believe the idle speed of the C-300 was changed if nothing else. Twelve pages of the 1956 AMA specs were published in the most recent Brute Force magazine and contained modifications into mid-April, 1956, primarily to add the 355 HP engine with 10.0:1 heads. 1956 exhaust pipes for the "B's" are shown as 2.25" std, 3.0" optional-probably for the 355's. "300-B" tailpipes had swollen to 2" in 1956. With the NY tailpipe now spec'd at 1-3/4". I recall seeing a photo of the trunk of a '55 or '56 Kiekhaefer car that had the tail pipes running across the top of the trunk floor and out the rear panel below the trunk lid. Those tail pipes looked huge--3" or 4" and the routing avoided the problem of minimal clearance between the rear axle and frame and the likelihood of the tail pipe getting damaged or collapsed during the race and restricting flow. Probably a NASCAR rule allowed this as it would also minimize broken off pieces of tailpipes on the track. The standard 354 hemi 300-B engine had 340 HP with 9.0:1 heads. The NY also had the 9.0:1 heads and 280 HP at 600 fewer RPM and a single 4-barrel. 86.5 octane gasoline was specified for all 1956 engines, as compared to 85 (Motor) octane fuel for all engines in 1955. Anyone know whether that was regular or premium "Ethyl" fuel at that time? I think it was regular as I remember working in a Clark station that sold only one grade of gas-Clark Super 100 and it was lower octane than major brand "Ethyl", but worked well in most cars of the mid-late '50's. C-300'ly, Rich Barber Brentwood, CA 1955 Chrysler C-300 (218.6"L x 60.1"H x 79.1"W, 43'-9" turning diameter-curb-curb) [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 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! 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