Finding the engine block numbers on a 68 427 BB

[Khalid A.]

I recently bought a 68 coupe and I would like to know where I can find the engine block numbers, I would like to know if it is the original motor. I am a bit of a novice so any help would be appreciated and needs to be in plain English . I am told the car is a 427 BB and I am fairly confident this is the case from the hood, the car also has a a 4 speed stick shift and has a Holly 4brl carb.

[John C.]

Re: Finding the engine block numbers on a 68 427 BB

Khalid

There are 3 spots to check to get all the numbers for your engine. I've attached some pictures to help you locate the info.

First is the engine stamp pad. It is found at the front of the engine block on the passenger side. If it is the original engine it will be stamped with engine assembly information, as well as, the the vin derivative of the car it was installed in.

Example T0408IR 18S416471

The stamped engine information will contain the engine assembly plant, the day it was assembled, and the suffix code to denote the type of engine.
T = Tonowanda
04 = April
08 = day of month the engine was assembled
IR = suffix code (L71 435hp in 1968)

If the engine is original, the last 8 characters in the vin derivative on the stamp pad should match the last 8 characters of your full vin number.

Second is the block casting number. It is found on a flange at the back of the block on the drivers side where it bolts to the transmission bell housing. It is right below the firewall. It is cast into the block and this one can be hard to read. For an original 1968 BB engine the casting number should be either 3916321 or 3935439.

Third is the casting date. This is the date the block was cast at the foundry. For an original 1968 BB engine it will be on the passenger side of the block just in front of the starter motor. The casting date is an alphanumeric code (example C28= March 2, 1968). The numbers are small and are very hard to read in many cases.

On later BB engines the casting date was moved to the transmission bell housing mounting flange on the rear the block on the passengers side.

John

[Khalid A.]

Re: Finding the engine block numbers on a 68 427 BB

Many thanks John, the pictures are a great help.

[Khalid A.]

Re: Finding the engine block numbers on a 68 427 BB

Hi again, I managed to locate engine stamp pad and I took down the number T0812M6J8, but I'm not sure if it makes any sense, I was hoping you might be able to help. I also took down the manifold number 3880828-RH which appears to be consistant with a 427 big block. Thanks again

[Joe L.]

Re: Finding the engine block numbers on a 68 427 BB

Hi again, I managed to locate engine stamp pad and I took down the number T0812M6J8, but I'm not sure if it makes any sense, I was hoping you might be able to help. I also took down the manifold number 3880828-RH which appears to be consistant with a 427 big block. Thanks again

Khalid-----

The "T0812" indicates an engine block assembled at Tonawanda, NY on August 12. The year will be indicated by the block casting date located on the right lower side of the block. The date on the stamp pad should be followed by a TWO character code of two LETTERS. All 427 codes for 1968 began with an "I". The "M6J8" you report "does not compute". You might want to check that again to see if you are reading it correctly.

The 3880828 is the correct casting number for the right side manifold used for all 1968 Corvette 427's. It was actually used for all 1966-74 Corvette big blocks.

[Kenneth B.]

Re: Finding the engine block numbers on a 68 427 BB

Check the casting # & the cast date on the side of the block It would be a letter & two or three #'S

[Khalid A.]

Re: Finding the engine block numbers on a 68 427 BB

Thanks for the help Joe, I took a picture of the engine stamp pad and I can confirm the number is T0812 M6J8 - I will try to attach a picture to this thread. I also got the block stamp number 12550313 which seems to indicate a crate 454 engine and I also got FI 98 from the same area. So I suspect the original motor was replaced with a 454 at some point.
Engine pad.jpg

[Joe L.]

Re: Finding the engine block numbers on a 68 427 BB

Thanks for the help Joe, I took a picture of the engine stamp pad and I can confirm the number is T0812 M6J8 - I will try to attach a picture to this thread. I also got the block stamp number 12550313 which seems to indicate a crate 454 engine and I also got FI 98 from the same area. So I suspect the original motor was replaced with a 454 at some point.
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Khalid------

The the suffix code "M6J8" is not an original code but, apparently, one used for the very much later engine involved here. The 12550313 casting number, which I cannot identify, is most likely a Gen VI big block which means it's from the later 90's. Gen VI big blocks can be most easily identified by a plastic timing cover.