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I have a 327 based upon the casting number, but the stamp pad shows no sign of identity stamp. Guessing it’s been decked. I sort of remember reading something about using acid on the pad to try to see any remnants of the identity stamp. Is this something that can reveal a number on a decked block and if so what is the acid type and procedure used?
Does the pad showr signs of the original broach marks from when the block was originally machined. If they are still present then the block may have never been decked and may be an over the counter engine or warranty replacement engine w/o a stamping. I think you are right that sometimes the stamping can be made visible with treatment but I'll have to leave that to others to address.
Yes, broaching is clearly visible. I just gave it the acid treatment. Supposed to see results (if there are any to be seen) in about 30-45 minutes. I’ll check it tomorrow morning for results.
Best I can do on the pics:
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Drivers side casting number at top of block at bell housing: GM8782870
- Passenger side casting number at top of block at bell housing: GI33.....there appears to be a character before the “G” and after the second “3” both of which are pretty indistinguishable if they even exist. Best guess is prior to the “G” May be a “O” or “0”, and after the second “3” could be a “5” or “6” (or just a casting flaw).
- Front stamp pad: no signs of identity stamping, just some evident broaching (even after an acid treatment)
Does it have a 1/4” pipe plug just above/behind the water pump on the block?
My block does have the 1/4” plug you asked about. I have an orange arrow pointing to it in the included photo. What does that tell me? What is that plugged hole for?
From: Middle TN by way of KY, OH, VA, IL, CA, FL, NY, SC, HI
IIRC, that plug means your engine was cast and built in Flint, as opposed to Tonawanda where no Corvette sbc engines were cast and built. (Actually, I think it would mean it was cast in Saginaw and assembled in Flint).
If the pad shows authentic broaching, it’s likely not decked. Rather it’s an over the counter engine, 1963 870.
I agree 100%. To answer the question regarding using acid to "lift" the numbers: "nitol" would be one substance that would work. It is a mixture of nitric acid and alcohol in, I believe, a 50/50 ratio. I have used this to examine grain structure in steels. To give good results the ferrous surface should be polished as smooth as practicable. It is then immersed in the acid for about 15 min. and then washed in clear water & dried. Not to handy to do with the engine still in the car, but I guess it's possible.
This is not an area I am knowledgeable in, but I would have thought a replacement block would have some sort of stamp.
Some facilities did add identifying numbers/characters when installing over the counter engines as replacements or for warranty work. There is a a lot of info at this website regarding this subject and how Chevrolet addressed it. http://chevellestuff.net/qd/engine_stamp_numbers.htm
(John Z has addressed this in a number of posts as well in the past and is much more of an authority on the subject.)
Beginning January 1, 1968 the federal government requested voluntary compliance of identifying major parts of a motor vehicle by inscribing or affixing an identifying number or symbol on major parts. As far as research has shown, Chevrolet did comply. by stamping a partial VIN on all engine blocks(1). Again, the location on the block may vary between the plants and years but one change was made in 1968. The GM division number ('1' for Chevrolet) was added to the partial VIN. A 1968 version of an Atlanta partial VIN stamping would 18A174373.
There is another type of stamping found on some blocks. This is the "CE" code. You might see something like this "CE056789" on the front pad of the block deck on the passenger side. The "CE" stands for "Chevrolet Engine" but is often erroneously referred to as "Counter Engine", "Counter Exchange" and "Crate Engine" was used on blocks that were warranty replacement engines. If a customer had problems with his original engine, while it was under warranty, it was replaced with an engine that was stamped "CE" with a 6-digit number following it which serialized that particular engine. It's important to note that the "CE" designation for replacement Chevrolet engines did not start until 1968 so any year designation in the engine number would be for 1968 and later. The CE block stamp year is the year the block was stamped and not for what year of car the block was destined for since a generic block for fitted engine could be used as a warranty replacement for any number of years' engines, applications, and for cars produced from any assembly plant.
So I was able to confirm that this unstamped block was purchased from our local Chevy dealer over the parts counter in late 1963. My cousin bought it to put in his ‘59 Vette. Drove it for three years then gave the engine to my dad. My dad threw it in this 58 I now have. Probably not 10,000 miles on it.
So the casting date is July 13, 1963. Other than the stamp pad, how would you know that this engine didn't come in,say, an August 63 Vette? I am guessing there is other little stuff that would identify it as a service engine.
Decked block stamp pad question
