Oshawa engine stamping

davepl · Poncho Master!

Oshawa engine stamping

4SPEED427 · A Poncho Legend!

Are you talking 69 only? I think I can get you a 68 picture if that helps.

seventy2plus2 · Canadian Poncho Superstar!

Here's the stamping on the 70 454 Laurentian.

Not the best photo, but you can see the fonts and their alignment.

-- Edited by seventy2plus2 on Tuesday 9th of January 2018 09:54:19 PM

427carl · A Poncho Legend!

Here is some info on a 66 Cdn BB . and a poor photo that only shows the matching end letters . biggrin

4 days service.jpeg

4SPEED427 · A Poncho Legend!

I dug up this picture. Does this help?

davepl · Poncho Master!

Thanks! I wish my sequence number were a little tidier, I guess that's my only concern.

4SPEED427 · A Poncho Legend!

Yeah, the one I posted is kinda pretty compared to the one you posted isn't it!

But it's all part of how cars and parts were made in that era, far from perfect.

I saw a small block stamping once that was to close to the edge and they tried to wedge it all in a space too small. And I know it was authentic.

davepl · Poncho Master!

Yeah, I'd like to have a good explanation for why it's so sloppy. If they're ganged into a tool, they shouldn't be like that. They look like they were done free-hand, to be honest. One theory I heard is that the big square pipe plug that sticks out of the cylinder head on the big block interferes with the gang stamp. So they swap them for the location of the engine code, putting the sequence number in the lower right on big blocks.

But why would they free-hand it? Maybe the fact the tool didn't fit easliy prompted someone do big blocks by hand that day? But the 1970 454, a year later, is great and neat.

As I've speculated, if you're going to fake a T1220LA motor, you do it for a Chevelle or Camaro. And you don't do it 20 years ago, get the broach marks all perfect, and then be sloppy about the stamp. I'll feel a little better once I find the date codes.

-- Edited by davepl on Wednesday 10th of January 2018 02:54:35 PM

4SPEED427 · A Poncho Legend!

Just for information, George at GM Vintage Vehicle Services using only the engine number was able to document the car that the engine I pictured was originally installed in. It was a 68 Parisienne 4 door.

davepl · Poncho Master!

I guess that's true, there's only one vehicle with that sequence number. So if the last 7 digits of the engine stamp match the last 7 of the car, it's a match, and they should be able to pull documentation.

Similarly, since you know my bodystyle, you should be able to reverse engineer my VIN from the sequence number!

seventy2plus2 · Canadian Poncho Superstar!

The 9 digits of the stamping match the last 9 digits of the VIN. This was done by GM to prevent theft of the parts. The engine & transmission have the partial VIN stamped on them so they can be identified.

seventy2plus2 · Canadian Poncho Superstar!

It'd be interesting to see the casting # on the block. It should be:

3935439 early
3955270 transitional (Aug - Oct 1968 castings)
3963512 late

The LA suffix is correct for a 1969 427 Manual Transmission.

-- Edited by seventy2plus2 on Wednesday 10th of January 2018 09:19:35 PM

davepl · Poncho Master!

It's a 3963512, as loved by COPO Camaro and LS-6 Chevelle cloners worldwide, unfortunately! But it survived this long...

If anyone has a picture of the data location on a pre-69 big block, let me know. I can't find it! Only place left to look is under the driver's side exhaust manifold..

It appears the intake and heads were cast in Sept and the block assembled into a motor on Dec 20, then the car built in April.

-- Edited by davepl on Thursday 11th of January 2018 02:12:53 PM

4SPEED427 · A Poncho Legend!

davepl wrote:

If anyone has a picture of the data location on a pre-69 big block, let me know. I can't find it!

Dave, you asked for data location but did you mean date? If so, you are looking for the date code of the block only?

davepl · Poncho Master!

Sorry, yes, it's the DATE that I can't find!

4SPEED427 · A Poncho Legend!

I'll check but it may only be tomorrow. I think I have a picture of one with the date but I can't recall where it was on the block.

North · Guru

dates can be all over especially on low volume engines. For example my 69 Firebird sprint has its original engine but the block and head etc were cast almost 7 months ahead of the cars assembly. The VIN is obviously original on the block and the owner since 1973 (i bought it from him in 2010) wouldn't know how to remove an oil filter. In that case it probably related to the production switch from Lordstown to Norwood between my casting date and my car assembly date.

4SPEED427 · A Poncho Legend!

Carl Stevenson wrote:

I'll check but it may only be tomorrow. I think I have a picture of one with the date but I can't recall where it was on the block.

No luck, sorry Dave.

seventy2plus2 · Canadian Poncho Superstar!

Now that the body is off the frame, can you find the engine cast date? Any evidence of anything on the bellhousing flange behind the passenger side cylinder head?

SD 396 · Poncho Master!

seventy2plus2 wrote:
Now that the body is off the frame, can you find the engine cast date? Any evidence of anything on the bellhousing flange behind the passenger side cylinder head?

Clint is correct for the position of the casting date on the block. "letter" - "number" - "number". Sequence numbers were stamped in Oshawa as the engines were assigned to the car. The date stamp was done at the Tonnawonda Plant.

I had a 396 from a 1969 truck with terrible sequence stamping near the oil filter. It must have been stamped 4 times. All the blocks I've seen from Oshawa were pretty good though.

davepl · Poncho Master!

There's an unreadable blob on the bellhousing that could be the date. But I'm thinking my date is likely still on the side of the block, as they didn't move the 3963512 date until early 1969 and my motor was cast in Nov I think, and built in Dec.

seventy2plus2 · Canadian Poncho Superstar!

The in another thread you indicated the block was cast in November, 1968. Where did you finally find the casting date?

427carl · A Poncho Legend!

download (1).jpeg

davepl · Poncho Master!

On th earlier blocks like mine you'll find (a) a tall distributor boss inside the valley, and (b) the date code upside down on the side of the block by the passenger side pan rail. Mine said L2-8, which I assume is Dec 2, 1968.

-- Edited by davepl on Friday 19th of January 2018 10:45:19 AM

4SPEED427 · A Poncho Legend!

I don't think they used "I" in that sequence because it could be confused with other numbers/letters. It could well be November.