The "3-1 P 41" is engine number (it is stamped into the block ) while "2120529-4 on the sides" is the casting number. It is a 1960 engine : P 41 3-1 : P - 1960 model year 41 - 413-cid 3 - Month Assembled - March 1 - Day Assembled - 1st Chrysler Engineering used a letter code for the engineering model year, using letters : A B C D E F G H J K L M P R S T V The only exception to the above was the 1960 Valiant. It was model year "Q", and was the only Valiant not to be model "V", being model "X" for one year only. "A" years were 1924-25, 1942, 1965, 1982. Combined years were 1924-25, 1946-48, and 1951-52. Chrysler used the engineering code as the model year in 1958 and 1959 serial numbers and engine numbers starting in 1957. The VIN of Chrysler's European subisidiaries used the numbers in the 1970's as did Chrysler in Great Britain in mid-1930's. For 1955 to 1975 Imperials, the engineering model years were : H - 1955 J - 1956 K - 1957 L - 1958 M - 1959 P - 1960 R - 1961 S - 1962 T - 1963 V - 1964 A - 1965 B - 1966 C - 1967 D - 1968 E - 1969 F - 1970 G - 1971 H - 1972 J - 1973 K or 4 - 1974 L or 5 - 1975 Another little quirk of the engineering department was when a model was carried over more than one engineering model year (which was not always the same as the sale department model year). The 1934 Chrysler Custom Imperial Airflow, model CW, was built in engineering year K, and was carried over to year L (1935) with only sheet metal changes. As it used the same engineering model number, CW, the engineering number added "*". Thus the 1935-37 Chrysler Custom Imperial Airflows appear in Chrysler lists as CW*. Same with the model L. It was introduced for 1928 (model year D) and carried forward through 1929 (E) and 1930 (F) with no change. Thus the model number L* for the latter two years. And again with the 1932 CL (model year H) which became CL* for 1933 (J). When the engineering department made no changes for all models over a couple of sales department model years, the engineering codes did not change. Which is what happened with the 1946 models (year B). They were carried through to the first series 1949 and neither the engineering model years (B) nor the car engineering codes (C-40 for the Chrysler Crown Imperial) changed during that period. And it occurred again for 1951-52 (engineering E), with the Chrysler Custom Imperial (C-54) and Crown Imperial (C-53). Chrysler did not start putting the engine size with the casting number until the late 1960's and it was placed after the main number. Thus, the cast number on your car would have looked like : 2120529-413-4 Bill Vancouver, BC . > > In an email dated 5/8/2005 4:20:31 am GMT Daylight time, Joe Vanderzee <flying_dutchman0420@xxxxxxxxx> writes: > >I just picked up an old v-8 chrysler from a house I was renting for a while. The owner doesnt know where or what it is out of and I am just as lost. The only thing that set it off is it has a Imperial decal on the one valve cover. The only numbers I found on it are ...... >2120529-4 on the sides of the motor, and 3-1 P 41 in front of the intake on a machined pad. >I know chrysler liked to put the c.i. in the serial # but I have never heard of them making a 529 c.i. engine!!! I am just looking for some info from a large group of mopar people and hope you know what this monster really is. >Thanks alot. >JoeyV > > ----------------- 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