It probably is a freeze plug, blocked off by a previous owner for some reason, probably installed a pcv into a valve cover and did not need this to be open.
It is a freeze plug, a common practice when the road draft tube is not needed. A year Corvette used this for the PVC. Pat
I have also heard this and also don’t have anything to back it up. The other possibility could be a marine engine. I had a pair of small journal 327 marine engines that were original in the boat but can’t remember if the boat was built after 68. I have a marine block that’s a roller block that has a fully machined and functional mechanical fuel pump boss that would not be there on that year production automotive block. Sent from my iPad using The H.A.M.B. mobile app
More than once I heard the "seven year law" thing both before and while I was in dealership parts departments. Early on in my dealership years I asked our Pontiac Motor Division Zone Rep and one of the people at GMPD (General Motors Parts Division) about it. No such law I was told. The guidelines were that GM would keep parts available as long as there was a demand for it that would justify manufacturing it, the tooling. dies or other equipment to manufacture it was serviceable and the price to make the part was within an acceptable range. For example, this one comes to mind, the 1977 Pontiac Can Am. While the rear spoiler was not made by GM, a common thing even back then, the mold broke. Due to the cost for a new mold, low volume of sales and internal GM decisions that model of car was dropped and no service replacement spoilers were available. During the fall of 1979 when I was a parts manager the dealership's owner "horse traded" from one of his other dealer friends for a 10th Anniversary Trans Am, a 400 4 speed than had the side of the engine block punched out by a connecting rod. No big deal, right? Especially because it was under warranty. right? Wrong! Seems that GM marketing decided to offer a 400 that year without finding out that manufacturing had discontinued building the 400 previously. Seems the tooling for the 400 was gone so production scrambled to find blocks for assembly, this entailed raiding GMPD for any inventory they could get with no forethought of what would happen when a service block was needed. That one gave me some early onset gray hair. I found out that there was an earlier year 400 block available but there were some internal differences. It took some doing between my factory rep and his superiors to allow me to use that block, acquire the different parts to make the changeover (if memory is correct pistons, crank and heads were different) and put it all together. It was that or PMD was going to have to do a buyback on that car. GM at least when I retired three years ago can and will discontinue parts due to lack of demand, expense of manufacturing, supplier unwilling to make or goes out of business, contract pricing, about anything they want to. I saw the first occur more rapidly post bankruptcy. Not as likely for a slow moving part to be available as it costs money to store it on a shelf, if they maybe only sell a thousand in a year it will probably go away. Lansing PDC (Plant 76) used to be the "elephant graveyard", the place where slow moving items like soft trim went to die. The last couple of years I was in the amount of soft trim items for two and three year old cars that were discontinued was surprising to say the least. At one time the dealerships would get a listing of parts to be discontinued. I would get those lists and go over them for interesting items. As I had two or three people in the restoration parts business I would call and advise them of this and buy up the stock for resale to them. Sometimes it was 5 to ten pieces, sometimes in the hundreds. Gm stopped that practice before the bankruptcy, they would just scrap it out. But back to the engine block discussion, if memory is correct the CE designation was used for service replacement engines. Early on in the 70's blocks could come through with or without stamped numbers on them depending where they came from and if it was originally designated as a production or a service engine block. No rhyme or reason for some things such as seeing a 1970 350 2 bbl fitted block in the crate with the low compression pistons and four bolt mains. Early (1973) engine blocks coming through in the crate from GMPD painted and stamped with engine ID but no partial VIN, like they were diverted from production. I sold a LS-7 BBC in 1975 over the counter once with no numbers. This prompted a visit from two PD Detectives who were investigating a alleged chop shop as the guy I sold it to gave them a receipt and they did not believe that GM would have sold an engine with no serial numbers. I took the two of them to our bulk storage area and said "Look for yourself, about half will have no numbers, some will have numbers." To say the least they were not too happy when they found out the owner of the engine was telling the truth.
As shovelheadrider said above "no rhyme or reason" why GM did certain things back then. For instance, arguing what did and didn't happen based on what the sales brochures showed or why some things that were shown in the assembly manuals but never made it to production. A lot of "front office" politics and bean counting ruled the day in the 60's/70's.
Back in 1966 when I was working in a garage during summer break from undergrad school, a lady brought in a '57 Belair 4-door sedan for an engine overhaul.....2-barrle/283/automatic trans. When we took off the heads we realized it was a 283 fuel injection engine, heads, solid lifters and all, except with a 2-barrel. No telling what you would get from GM back then.
I can verify these castings were used for counter exchange C/E (deck pad stamped) block into the early 70’s 68-72 ish and your block is a 71 variant I had one that I got a good deal on, that was only bought for the steel 327 small journal crank that was inside it that i needed for a early chevy 2 block build. one thing for sure is these 3959512 blocks are HEAVY. and i mean significantly more weight than any other small journal 283 or 327 block that I have manhandled into the back of the truck. in fact i can just move a early chevy 2 283 and 327 bare block by myself in and out. but that late 60’s early 70’s 512 327 bare block casting forget it....it just tipped the scales at more than i could handle. (they are dense)funny thing the early chevy 2 blocks were both 283/327 and I have moved several without issue. BUT they must have reinforced the 512 casting or added nickel or something cause they are TANKS !! for a 2 bolt main. the one i had was std bore 4” and almost no cylinder wear taper. I see why guys snap them up. their stout the 512 block i sold had a road draft tube provision.
The Jalopy Journal
