LS4 Cylinder Block Casting Number

[Joe L.]

Re: LS4 Cylinder Block Casting Number

Good follow up Mark. I understand its not a judging points issue, but, only a what the X do the embossed markings represent? Is this the case on all "T" C2, C3 big blocks? No mention in '73-74 tech manual regardeing these markings.

George Hunt

George-----

All 1965-74 big blocks were cast at the Tonawanda, NY foundry and have the "T" casting mark. The Tonawanda foundry was very good about seeing to it that the "T" appeared on all of their castings, blocks, cylinder heads and otherwise. Of course, there might be some minor exceptions. For Saginaw foundry castings (most Corvette small block castings), there were rarely casting source identifier marks although a few are seen with an "S" embossment.

For the GM St. Catherines, ONT foundry (many small blocks but not Corvette), a "K" casting identifier is seen.

[George H.]

Re: LS4 Cylinder Block Casting Number

Good follow up by everyone. I now know what the embossed stampings represent. I should have taken a picture first and then asked the question with the picture. Got me thinking after posting the question and getting some comments back that I better check it out. That's when I took the picture and posted it. Glad we have some very knowledgeable members on the NCRS technidcal side.

George Hunt
Ocala, FL

[Joe L.]

Re: LS4 Cylinder Block Casting Number

Good follow up by everyone. I now know what the embossed stampings represent. I should have taken a picture first and then asked the question with the picture. Got me thinking after posting the question and getting some comments back that I better check it out. That's when I took the picture and posted it. Glad we have some very knowledgeable members on the NCRS technidcal side.

George Hunt
Ocala, FL

George------

Well, I must apologize for an error I made in my recent post. The embossment "P" on the bellhousing flange was used for most passenger car blocks dating back to 1965. The embossment "PASS" was found on the front of the block under the timing cover. "HI PERF/PASS" was cast in this area on 4 bolt blocks with provisions for an oil cooler.

So, all of this should have occurred to me with your first post without photos and I should have answered simply that it refers to a passenger car block. It makes me worry that I'm slipping. After all, making multiple errors on responding to what should have been a simple question.

[Rob V.]

Re: LS4 Cylinder Block Casting Number

Hi Joe--

I do not believe that you are "slipping"--far from it!!

[Owen L.]

Re: LS4 Cylinder Block Casting Number

As long as we're identifying casting codes, my '72's original block (also 3999289) has one I've not been able to figure out: it says "CONV1". I've seen photos of other blocks with "CONV2". Pretty certain it doesn't mean convertible!

"Conventional"? And why #1?
Note that my block doesn't have the P on the flange (it's not on the other side either - just the date code). As I recall, it says Hi-Perf Pass under the timing chain cover.

454 casting.jpgIMG_0637.jpg

[Joe L.]

Re: LS4 Cylinder Block Casting Number

As long as we're identifying casting codes, my '72's original block (also 3999289) has one I've not been able to figure out: it says "CONV1". I've seen photos of other blocks with "CONV2". Pretty certain it doesn't mean convertible!

"Conventional"? And why #1?
Note that my block doesn't have the P on the flange (it's not on the other side either - just the date code). As I recall, it says Hi-Perf Pass under the timing chain cover.

[ATTACH=CONFIG]120069[/ATTACH][ATTACH=CONFIG]120070[/ATTACH]

Owen------


Very vaguely, I seem to recollect that the late Mark Gorney who worked at the Saginaw foundry for many years once said that the "CONV" referred to "CONVEYOR".

Also, note the differences in the embossments on your 3999289 block versus the 3999289 block of George's. Note also that your block is pattern number 10 while George's block is pattern number 12. These are exactly the kind of minor differences that can happen of castings of the same part number but different pattern numbers.