Help decoding 230ci engine stamp

[Praxiss454]

This is a bit of a cross-post from another thread, but no one had an answer and I thought moving the engine-specific question here might yield some more help. Hope this is okay.

I have a 65 GMC 1000 with what appears to be an original engine, but the stamp on the engine leaves me puzzled. The block casting number (3850817) says this is a 62-78 230-250. I assume the bottom half was painted at some point after the fact w/ that blue color, when the PO was doing some maintenance.


However, the engine stamp appears to be F0904Z01 and then a much fainter "238" (I think, can't quite make it out)
From various decoder websites I gather F - Flint, 0904 - Sept 4. What about the rest of it? Was hoping to be able to confirm that this was the original engine, OR identify what kind of vehicle this one came out of.


Thanks

[TJ's Chevy]

To tell if it is a 230 pull a plug and look at the piston. If it is flat top you have a 230. If there is a D style dish in the piston you have a 250. If it's a 230 it will more likely be original. People who swapped out the v6 for s straight 6 usually went with a 250 or 292.

[Praxiss454]

Thanks TJ's Chevy, I will do that to confirm that it is a 230. But why would the stamp have a code I am unable to find on any decoder chart?

I obviously have a lot of clean up to do still and I've read engines will have partial vin's also stamped on them but I haven't found it yet.

['68OrangeSunshine]

Originally Posted by Praxiss454

Thanks TJ's Chevy, I will do that to confirm that it is a 230. But why would the stamp have a code I am unable to find on any decoder chart?

I obviously have a lot of clean up to do still and I've read engines will have partial vin's also stamped on them but I haven't found it yet.

Two possiblities:
One, there were more codes on L6s than were accurately recorded or remembered by anyone still alive and not suffering from dementia.
Or Two:
When the engine was rebuilt someone added their own suffix to the existing engine dress code, for their own reason like inventory control, or to note features in that build.
Chevy Engine Orange paint is an indication it was messed with after Production. An unmolested '65 230 would be in the old Chevy Blue. Or is that Boxcar Red?
What year did GM stop producing the 230 in favor of the 250?
With the '67 Model Year, all Chevy engines [L6s and V8s] got a standardized Chevy Engine Orange. Partial VINs were not present on Truck Engines, Car engines, maybe.

One thing to think about -- if the block were bored out to .060 over, the displacement would go up to 237 CuIn, according to Leo Santucci's "Chevy Inline Six Cylinder Power Manual". A different machinist might calculate '238' and stamp that on his rebuilt block. Who knows?

[TJ's Chevy]

Originally Posted by '68OrangeSunshine

Two possiblities:
One, there were more codes on L6s than were accurately recorded or remembered by anyone still alive and not suffering from dementia.
Or Two:
When the engine was rebuilt someone added their own suffix to the existing engine dress code, for their own reason like inventory control, or to note features in that build.
Chevy Engine Orange paint is an indication it was messed with after Production. An unmolested '65 230 would be in the old Chevy Blue. Or is that Boxcar Red?
What year did GM stop producing the 230 in favor of the 250?
With the '67 Model Year, all Chevy engines [L6s and V8s] got a standardized Chevy Engine Orange. Partial VINs were not present on Truck Engines, Car engines, maybe.

One thing to think about -- if the block were bored out to .060 over, the displacement would go up to 237 CuIn, according to Leo Santucci's "Chevy Inline Six Cylinder Power Manual". A different machinist might calculate '238' and stamp that on his rebuilt block. Who knows?

There were several codes in which I was not able to decode. So I completely agree with there being to many. haha I believe the 230 was dumped by the early 70's. It was available in camaros for a short time and then they upgraded to the 250.

[Praxiss454]

Originally Posted by '68OrangeSunshine

Two possiblities:
An unmolested '65 230 would be in the old Chevy Blue.

I'm having trouble finding the thread that mentions it, but I believe in 1965 there was a bulletin that GMC L6 engines (including the 230 which I believe I have) were to switch to the red color, same as the V6s.

[TJ's Chevy]

This picture shows them in red.

www.6066gmcguy.com/Inline6.html

[Praxiss454]

Found the other thread, here. User factorystock posts what appears to be some kind of bulletin for 64/65 GMC 230 and 66 GMC 250s: To improve product identity, all GMC gasoline engines are now painted the same red as the V-6's.

But as '68OrangeSunshine mentions, the stamp could have been appended at a later time, so who knows. Maybe as I clean things up more I will uncover more info.

['68OrangeSunshine]

Oh, OK. I never noticed that the GMC powerplants were a different color than Chevrolet. I guess it is that color I called "Boxcar Red".
On the Chevy line 230s and 250s were blue, and 292s were "Alpine Green".
In 1967 Chevy painted all engines Chevy Orange.
I even painted the valve covers on the crate engine in my '71 Jimmy K/1500 Chevy Orange in my benighted ignorance. Now I must live with it. Oh well.

[TJ's Chevy]

When I took the old 292 out of my 66 chevy I noticed the back of the head was an orange/reddish color. Indicating at some point that the head was redone or worked on. 292 would have been green so why they went red beats me. haha Ran the numbers and they show to be that year so.

['68OrangeSunshine]

Originally Posted by TJ's Chevy

When I took the old 292 out of my 66 chevy I noticed the back of the head was an orange/reddish color. Indicating at some point that the head was redone or worked on. 292 would have been green so why they went red beats me. haha Ran the numbers and they show to be that year so.

If it was a 292 out of a GMC it may have been original 'boxcar red'. [That's the name of a color of Floquil model train paint, not an auto industry shade, but it's closest to the right hue.] It's also the color of manual transmissions, IIRC. So according to FactoryStock's notation of a GMC corporate directive, they went with all Red engines in 65/66, with Chevy following suit in '67 in their Orange color.

[TJ's Chevy]

Originally Posted by '68OrangeSunshine

If it was a 292 out of a GMC it may have been original 'boxcar red'. [That's the name of a color of Floquil model train paint, not an auto industry shade, but it's closest to the right hue.] It's also the color of manual transmissions, IIRC. So according to FactoryStock's notation of a GMC corporate directive, they went with all Red engines in 65/66, with Chevy following suit in '67 in their Orange color.

It was a chevy 292 for sure as the color on the block was green. That head had some valve train issues for sure though.

[Lugnutz65]

Look for the casting numbers. They can be found on the PS block just above the starter.
Here is my 1965 230 block.
CON 2 = Conveyor #2
F = is the 6th month = June
29 = 29th
5 = 1965

It means my 1965 block was cast on June 29th, 1965.

Now it's your turn. Can you decipher the other picture?

[Praxiss454]

Originally Posted by Lugnutz65

Now it's your turn. Can you decipher the other picture?

Looks like Jan 3, 1964 on your second pic.

Mine is CON 2 but I haven't cleaned up the second set of numbers yet (cuz I didn't know to look for them). CON 2 was under what seemed like a quarter inch of gunk.

[Lugnutz65]

You are correct. Both engines are 230s.

[Praxiss454]

The casting on mine says I 2 4, which would be September 2, 1964. This lines up pretty well with the stamp date of September 4th and makes me think this is the original engine for my 65 GMC.

[Lugnutz65]

That pretty much guarantees that you have a 230ci. Use a feeler trough the spark plug hole to confirm the shape of the top of the piston.

[TJ's Chevy]

Or just use a small flash light and look through the hole. Easily noticeable, especially close to tdc.