cast # is 3916323.
2 sets of numbers on front pad.
the first set of numbers are T10I3IV,
the second set of numbers are lower and to the right on the pad are 18D119081.

the casting number 3916323 is your block number. it is for early 1968. block was released by eary june 1967 and was in production till june 1968, even some late 67 camaro's received this block. first 396 block to use the new spin on oil filter.

T1013IV is your engine code. first letter "T" is the assembly plant, Tonawanda, new york. next two digits are month, 10= october. the "13" is the day of month or 13th day. and finally th last two letters "IV" are called the "suffix". IV shows car was a "turbohydramatic" for a 396/325 hp for 1967 passenger car, and same for 1968, and for 1969 the 350 engine for a passenger car.

the last number 180119081 appears to be part of your "vin" number (vehicle identification number). vin numbers from these years carried 13 digits. i believe you are missing the first 4 digits _ _ _ _ 1 8 D 1 1 9 0 8 1.

starting with the 5th digit 1, this is the second number in a sequential code, there should be a number preceding this number. this 2-digit number will identify the "body style" of your car.
the 8 identifies year or "1968". the D is for "plant" or atlanta,ga. the 119081 is a "sequence number. all passenger cars in 1968 began with a 1, all chevy II and all chevelles's as well. this was the 19,081 car built.

hope this helps. you will get more response to questions like this if you post them in the "tag" room. dave

Choo Choo, thank for the info! Would this motor be a numbers matching type for a 1967 chevelle built in late december?

18D119081 is the correct format for the partial VIN stamp on an engine:
1 = Chevrolet (2=Pontiac, 3=Buick and 4=Oldsmobile for example)
8 = 1968
D = Doraville
119081 = VIN Sequence number starting at 100000 which makes this the engine from the 19,081st full size Chverolet to roll off that particular assembly line.

This is not a "matching numbers" engine for any Chevelle. The "IV" is a code specific to 1965-68 full size Chevrolet 396/325HP w/TH400.

Dave

Dave,
Thanks for the info,I had this engine rebuilt (30 over) and had the TH400 gone over too,they are both in my garage and If I could use the big block I would,but now I am going to sell them and use the money towards my frame of restoration.