Bigchucker

I have just purchased a '78 pace car. The car is in mint condition inside and out, it has 15000 original miles, I think. The engine compartment is mint, every thing looks new and original as far as I can tell. It doesn't look like any nut or clamp has ever seen a wrench! HOWEVER, the VIN on the engine block is missing? faint blue paint still on it though. No number next to oil filter either. engine casting number is correct for 1978. Can it still be original, or perhaps the block was replaced at the factory?

Priya

Sounds like the engine was rebuilt and the engine VIN number machined off.

joewill

look for the engine casting date back behind the distributor.. should be before the build date of the car.

7t9l82

Priya may be right or perhaps it was faintly stamped. Run some sandpaper on the pad and see if it's visible.

Bigchucker

The only thing resembling a date code on the engine block similar to where casting number is but on passenger side is "71" in between what looks like 2 flat head screws?

gbvette62

You never want to take sandpaper, or anything abrasive, to an original stamp pad. Thinner or paint stripper is the way to go, if you want to preserve the broach marks.

7T1vette

Rebuilding the engine with only 15K miles on it????

Engine was either replaced or rebuilt..but car likely has more miles on it, if that is the case. What documentation proves 15K miles? (other than the odometer)

hunt4cleanair

Can you post a good quality photo? Once you have seen a number of these, what becomes apparent is that not much engine paint was used on the engine block...and it was quite thin. If coverage is complete on the oil pan and on and around the valve chain cover...then it was more than likely repainted for some reason.

This link is to a write-up I did on my 78 and shows the block stamp. The original would have had paint on it...but not much!

Matching Numbers

Alan 71

Hi Bc,
"or perhaps the block was replaced at the factory?"
Engines that failed while at the factory were known to be repaired or replaced, but the engine would still have had the engine assembly information, (that was done at the Flint engine plant), and vehicle identification information, (done in St.Louis), stamped on the pad.
Regards,
Alan

Easy Mike

Is the engine ID stamp still on the pad? Post a pic.

Bigchucker

Attached are 2 pictures of the pad and one of what I think is the casting date code for the block. Anyone see anything that would help.

drwet

Definitely looks like a blank stamp pad. Also looks like the block has never been decked. Notice the straight scratches on the stamp pad. This is indicative of a factory finish. If the numbers had been milled off when the engine was rebuilt, there would be a circular pattern from the machine work in decking the block. Not sure how to explain this as there should be two stampings on the pad. One to identify the engine, and another with the serial number of the car. The engine number is stamped when the engine is built. The serial number is added when the engine is installed in the car. Unlikely they would forget to stamp both. Possible the engine was rebuilt by the dealer using a factory replacement block?

7t9l82

thousand grit or finer paper would take alot of work to erase broach marks. You could clean the pad well and wipe some white out over it the. Wipe the pad.

68ACADIAN

A '78 with a '71 block? I wonder what the casting number is? Very strange but like they say truth is always stranger than fiction. It wouldn't be the first time GM did something odd at the factory while assembling their cars.........

Bigchucker

The date code...why is it not 4 digit with the first being a letter?

7T1vette

Blown engine; replaced with something that was 'available'. The replacement may have been properly machined and rebuilt...which is why the pad was clear (after the block was decked).

Alan 71

Hi Bc,
It looks to me like there is more to the casting date that's hidden in your photo.
Regards,
Alan

An engine block with a stamp pad in that shape wasn't being cast in 1971.
The mold didn't exist.

Alan 71

Hi Bc,
It looks to me like there is more to the casting date that's hidden in your photo.
Regards,
Alan

An engine block with a stamp pad in that shape wasn't being cast in 1971.
The mold didn't exist.

Here a typical sb casting date from the early 70s.
L31 0
January 31st, 1970.

Bigchucker

Casting number is 14016379, which I've read is 1979 and later. However, I emailed GM Heritage Centre and they said that code could also be correct for 1978. They also said "odd" things happened at factory where markings are missing or in different spots. Everything is still unclear. Any other way to prove that is the correct block?

Bigchucker

What happened if the engine blew after installation before delivery. Would it be replaced at factory and what would be stamped on the pad?