>From the info I have seen, the truck manifolds were not part of the 355 HP package. Were they used on the NASCAR engines? Good question. I suspect they were because NASCAR rules seemed to allow bigger exhaust . A Kiekhaefer by the name of Fenrich was in charge of the dyno room, I believe. Carl K. was meticulous about dyno runs for all race engines. Rumor is that the hottest engines were put into the race cars for the best racer, some politics could have been involved as well, per Tim Flock. To my knowledge, the Kiekhaefer records are still not in a position of being accessed. When that day comes, perhaps many of your questions will be answered. Dan -----Original Message----- From: Chrysler300@xxxxxxxxxxxxxxx [mailto:Chrysler300@xxxxxxxxxxxxxxx]On Behalf Of RLS Sent: Tuesday, May 06, 2008 12:39 PM To: Rich Barber; Chrysler300@xxxxxxxxxxxxxxx; Dan Elliott Cc: us@xxxxxxxxxx Subject: Re: [Chrysler300] 1955 AMA Specs (Last update?) Is there any information on how the 355 hp head was achieved? Was it a mere milling of the 340 head, was it a thinner head gasket, WAS there really a different part number for the 355 head. My understanding is that the only other changes for the hp increase was the use of the Dodge truck exhaust manifolds(I have pair of them) and a larger diameter on the exhaust piping. Seems to me with a 1 point increase in compression plus the exhaust system upgrade(and likely carb jetting and ignition timing changes to capitalize on these changes) that a mere 15 hp change in output sounds a bit conservative. Would really be of interest to find if any of these old race engines had dyno runs to measure true hp and how it may have compared to "factory stock" engines. As an aside to achieve 139 mph in the flying mile on sand at Daytona with a car with the aerodynamics of a ship's sail seems quite a stretch with a 340 hp(gross hp in those days). I also would be interested in the rear axle ratios on these flying mile cars(there were several of them that ran in Daytona in 1956, a number of which exceeded 135 mph is rumored). With an engine that is pretty much out of rpms at less than 5,500, seems that a stock 3:54 Powerflite rear axle does not seem likely. Anyone else out there with information to chime in? With the suggested octane levels from 1956, does this mean that one could run today's regular fuel instead of premium? I know that there is a calculation that is made to arrive at today's octane number. This current octane number is a combination of the so called "research" and "motor" numbers in some formula to arrive at today's octane number posted on the gasoline pumps. Roger Schaaf 300 B Calyfornua ----- Original Message ----- From: Dan Elliott To: Rich Barber ; Chrysler300@xxxxxxxxxxxxxxx Cc: us@xxxxxxxxxx Sent: Tuesday, May 06, 2008 8:19 AM 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] [Non-text portions of this message have been removed] [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! 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