I have a 340 engine. I'm trying to determine what year the engine is. I located the stamped info at the base of the head on the driver's side. I have looked on different threads that explain the stampings. I don't understand what they mean about a 10,000 day calendar, when they talk about the manufactured date of the engine. For example, 3174 means April 6, 1970, based on a 10,000 day calendar.
Engine Build Date
- Thread starter money pit
- Start date
Vaanth
Well-Known Member
The Chrysler 10000 day calendar is a date coding scheme. The beginning day of the first 10000 day range was Saturday July 29th, 1961, and the days count sequentially from then. The 1970 model year range of days is 2895 – 3259. Tables are in the factory parts catalogs, and as you noted, 3174 = April 6, 1970. Tables/charts and calculators for the dates are also available online. The following image shows the table from the 1970-1971 Parts Catalog:
The information on the front block edge below the left cylinder head identifies build information for the engine. The following example shows a breakdown of this information:
FM340 P 3174 0450
Where:
F = the model year, with F denoting 1970
M = the build plant, with H denoting the Mound road plant
340 = the displacement, 340 cubic inches
P = Premium fuel required
3174 = the build date, specifically, April 6, 1970
0450 = the sequential number of the engines built that day, specifically, the 450th engine
The following are listings of general codes for all engines, but not necessarily all codes:
Model Years:
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
M or 6 = 1976
N or 7 = 1977
Engine Assembly Plant Codes:
K = Toluca, Mexico
M or PM= Mound Road, Detroit, Michigan
MN, NM or MV = Marysville, Michigan
T or PT = Trenton, Michigan
W = Windsor, Ontario
Detail Codes:
NOTE: The following varies in some years and/or applications, and combinations or specifics.
A = 0.020″ Oversized cylinder bores
B = 0.010″ Undersized main & rod journals
C = Special crankshaft & pistons
E = Cast iron crankshaft
H = Standard four barrel carburetor
H = Hemi when before displacement, ex. H426
HP = High Performance
LC = Low Compression
HC = High Compression
M = 0.001" undersize main bearing journals
MP = Maximum Performance
MX = All main journals .0010" undersized
OS = 0.005″ oversized valve guides/stems
P = Premium fuel
R = Regular fuel
RX = All rod journals 0.010" undersized
S = Service engine (found on warranty blocks)
SP = Special engine, (ex. T/A 340)
T = Truck
WT or TW = Water Tested
X = 0.010" Undersize crankshaft journals
2 = Second shift
3 = Special high performance
♦ = 0.008″ Oversized tappets
✠ = 0.001″ Undersized crankshaft journals
✠ with X = 0.010″ Undersized crankshaft journals
Last edited:
Such a complex way to code the details. I'm having a problem decoding the stamping on my engine. The car was originally a 383 2 barrel. It was converted to a AAR clone by the previous owner. The 340 needs to be rebuilt so I want to be sure I have the proper year.
MoparCarGuy
Well-Known Member
- Joined
- Jun 28, 2020
- Messages
- 910
- Reaction score
- 799
Look at the VIN stamping as that will show the model year as part of the stamping.
Example: VIN ending in 0B379146 below (passenger side oil pan rail) shows zero "0" as the first digit which is the 1970 model year, B for Hamtramck Assembly Plant and the six-digit sequence number.
You can also look at the casting date on the side of the passenger side of the block to determine when it was cast. This would narrow down the model year as well.
Below example is casting date 6/17/71 for a 1972 340 (VIN stamping starts with a "2").
Example: VIN ending in 0B379146 below (passenger side oil pan rail) shows zero "0" as the first digit which is the 1970 model year, B for Hamtramck Assembly Plant and the six-digit sequence number.
You can also look at the casting date on the side of the passenger side of the block to determine when it was cast. This would narrow down the model year as well.
Below example is casting date 6/17/71 for a 1972 340 (VIN stamping starts with a "2").
Last edited:
Xcudame
Well-Known Member
Your 340 block casting is the none TA block 2780930 used between 68-73. The numbers on the block are what I think is a factory mistake. It should read 3888 0503 to make more sense. That would make it a 72 340 built on Monday March 20, 1972. A casting date earlier than March 20, 1972 would confirm my suspicion! And it would be the 503rd engine built that day.
Thanks. I'll take a look at the passenger side.
Similar threads
