3959512 large journal 4 bolt block
 

Hi guys, I stumbled across a block and was wondering what it was. Im an engine machinist and didnt have a clue as to what this was. I did a google search, and seams like its kind of a rare bird, I founda lot of info on this site. I think I have one thats even more rare. I have a standard 4 inch bore, large journal,with a vent hole and 4 bolt main 3959512 block, it does hace CE on the front pad, I dont know what kind of starting asking price would be reasonable for this block. I also have several other283 and 327 blocks,427 heads and dont know where the best place is to sell this stuff.I prefer to stay away from ebay(just because its a pain) any tips or suggestions would be great, thanks

Just "happened to stumble across this stuff" so you thought you'd sign up here, eh?

:D:lurk:

Ebay is still the best location to sell your items. Large viewing base. Costs a fortune for large items to the buyer for shipping.

Google it and you'll find a lot of info. Appearantly it was a `62-`67 327 block sold for racers. Thicker walls than standard and 2 bolt but some may have been converted to 4

Where are you, I'm interested... But only if I can inspect the block

Harry

west michigan, Ill get the date code and stamp off the front pad tomorrow and let you know tomorrow.

The original 512 casting is/was a 62-67 small journal 327 block.
LATER replacement bare blocks/short blocks were somewhat of a hybrid. That is, they had features of BOTH 67-earlier and 68-later blocks. This permitted using the block in a 67-earlier replacement application for engines that used a road draft tube and/or a fitting in the rear hole to permit plumbing a PCV valve.
For 68-later applications, the rear hole could be plugged and valve covers with holes and a twist-on oil cap could be used and the PCV valve plumbed into the valve cover.
I am somewhat familiar with this 512 block you have because I have one in one of my cars with a 77 casting date. NO PRODUCTION BLOCKS received the rear hole for crankcase ventilation beginning with 1968 vehicles-----------------they all used valve covers with holes.
Also, you mentioned the block was stamped with with a CE-------------------------that is a service replacement block, which means it was PROBABLY cast AFTER 1967 production engines. Therefore, IF, big IF, it was cast after 67, but had features to allow it to be compatable with 67-earlier cars (such as the rear hole for crankcase ventilation), then it would have the large journal crank bores and the different pad for a spin-on oil filter.
Now, regarding the 4-bolt mains. As I pointed out above, this would be a REPLACEMENT block, cast AFTER 1967. NO, I repeat, NO 4-bolt main blocks were used in production UNTIL the 69 models. I DO NOT KNOW of any authoritative documentation that confirms the manufacture of a 1968 4-bolt main production block. Thus, if no 4-bolt main production blocks were made in 68, then it is HIGHLY UNLIKELY that any replacement 4-bolt blocks were made in 68.
One thing that has NOT been provided by topls69 is a casting date. If the casting date indicates the block was cast AFTER Sept 1968, then it is possible it could be a factory 4-bolt block. Otherwise, as already pointed out, it could have easily been converted by a machine shop to 4-bolt.

Tom Parsons

In addition to being a production block from 62-67, I believe the 3959512s were also service replacement blocks for a number of years. I have one with a 1970 casting date, large journals, and 4-bolt caps. Mine's been decked, so the pad is blank, but a CE on the pad probably indicates it was a warranty replacement. My guess is the 4-bolt configuration was from the factory--based on postings by JohnZ, the warranty replacement engines were machined and built to whatever configuration the original (failed) engine had. So, they could be 2-bolt or 4. If you find one, you don't know what you have until you take it apart.

EDIT: posted at the same time as DZAUTO.

One significant side note about one of these 512 style replacement blocks.
For ANYONE who owns a 67-earlier car, and wants BIG displacement in a small block, and wants to retain the ORIGINAL appearance, this is the perfect "cake and eat it too"!
With the hole in the rear, it will permit using the 67-earlier style crankcase ventilation system, RETAIN ORIGINAL VALVE COVERS (such as early finned alum covers) WITHOUT HOLES, but yet stroke it with a SB400 style crankshaft. Thus, replacing a tired 327 with a 383 torque monster (make your 57 Chevy look like it has a stock 283). :thumbs:
I wish I had 10 of these blocks! :D

Tom Parsons

The 3959512 and that whole series of 39595xx blocks were replacement castings for the out of production 283 and 327 blocks beginning in late 68 early 69 when the CE program started. Any replacement engines/blocks before 68 would have used current production engines/blocks. After 69, those small journal blocks were no longer used in production. GM recast the blocks with new casting numbers to service the small journal requirements as follows.
3959532 283 PASS/TRUCK CE
3959534 283 Chevy II/Nova CE
3959512 327 PASS/TRUCK 327 CE
3959538 327 Chevy II/Nova CE

I have a 3959532 283 and a 3959538 327 Chevy II and both were cast in 69. Don't know if they are large or small journal since the pans are on them.
The 3959538 was a warranty replacement shortblock in my 67 Nova and was an L-79 configuration.

I have a later one (I think from 73) which is still a small journal and two bolt main. It is 3959512

The small journals are a little bit surprising if it was cast in 1973. I understand that all production SBCs (including 327s) were switched to large journals starting in 1968, and I always assumed that was for commonality and efficiency. I wonder if they kept the small journal machining operation?

If the casting date ends in "3", maybe yours is actually a 1963 production block?

well the font was really small on the casting so I thought it was a later block. Did the font and size change for the 512?

The 9512 block never had a production application; it was produced exclusively for 4"-bore Service and "CE" 5/50 warranty replacement usage, in both small-journal and large-journal versions. Most of them were cast at the Saginaw Service Foundry and machined at the Saginaw Service Engine Plant. :thumbs:

The 512 block in my 64 built Sept.1, 1963 has a casting date of H-18-3 or Aug. 18, 1963. A recent rebuild showed it to be a small journal. It has a blank pad and no CE marking. Since the bore and pistons were original I don't think it had ever been decked. It is date correct for the car so it must have been a service replacement quite soon in the car's use. :thumbs: Dave

John, thanks for the info. Just curious, could one made in the 70s have small journals?

Interesting. I have a 327 (365) engine that I purchased from GM across the counter in about '72. When i can I'll take a look. I believe it to be small journal. I know it to have the forged crank and domed forged pistons and 30/30 cam solid lifters. The stampings are very faint, but as I remember is was CE. Parts manager told me I got the last one as he had lots of difficulty obtaining it and it was removed from the parts book next edition. Actually as I recall, it was removed from the new parts books before he received it. Didn't think he'd get it at all.

I have a 512 in my 54. It was made in 1971 and has large journals.

Yes - they were machined for both SJ and LJ applications. :thumbs:

The 512 CE block I bought new from Chev in 1976 as a 327/350 short block, was cast in March 1970, and assembled in 1974 according to the CE number on the stamp pad.

It has small journals (guaranteed, I did a ring and bearing and rod replacement about 3 years ago), and now powers my '37 Ford pickup, after performing well in the '651 Corvette for 30 some years.

Doug

seams like theres a lot to know about these blocks, I have a machine shop and have seen 10's of thousands of small blocks and never came across one of these. the date code is D ? 6 (2nd number is not clear) the pad stamping is CE6P23780 maybe someone knows how to decifer the stamp also.

and the block came from the factory a 4 bolt, not converted by a machine shop.

That would be 73, not 63.

I agree, these blocks are probably somewhat rare, but they DO exist. I personally can testify to this because I just built a 383 from one for my 51 Chevy. It is dated Jan 77. The hole in the rear of the block permits the use of a road draft tube and early finned alum Vette valve covers WITHOUT any holes! :thumbs:

Attachment 48184570

Tom Parsons

Not sure why you say this. It fits the description of a pre-68 engine as described in Post #7 above by DZAuto about the history of the 512. Small journal, two bolt main, no CE on the block pad, rear vent tube, original style steel valve covers. Other posts above also seem to verify my thinking. Could you explain further, please? :thumbs: Dave

http://forums.corvetteforum.com/pict...ictureid=84339

The pad stamp says it was made at Flint V-8 in 1976. :thumbs:

The 3959512 block casting number did not exist in 63. It began with the CE program in late 68/69 and was for service use only.
The only 327 bock casting in 63 was the 870.

Big journal
 

I'm not clear on the block differences between one's with road draft holes and those without. Could someone post pictures showing the differences.
Thanks, Fast Jimmy

my 512 327 block is 63 and has small journal forged crank two bolt mains. price i paid two years ago still in crate $1250 less heads and cam shaft ! the selling section on this forum would be best .hearing the words from jim glass I have a 327 crate motor FS were welcome words .

I have been looking for a 383/400 that would allow me to use the finned valve covers....(looking for a sleeper for my 63)...didnt know this block was what Im looking for.
Whats a decent price for one of these, and is the small journal more desirable for a 340 clone?

Photo below shows the rear vent hole in the top of the block, and the hole in the rear wall of the lifter valley for the oil separator can; photo is a '65 870 block, and the 512 block is identical. '68-up production blocks didn't have either large hole. :thumbs:

512 Block
 

And, to confuse things more, here is a picture of a 512 block without the breather hole.


Attachment 48184571

I give up.

But it has the cast in pad for the hole. So it could be machined to accept the breather. Later blocks did not have the pad.
:cheers:
Harry

now mine could even be 73 cast with vent hole in rear of block and get this my block accepts a new style filter after removal of canister oil filter adapter. also machine shop that broke it down said it had 0010 block castings inside .I have to get a look at pad ID # and post later on .small journal forged crank two bolt main caps .

Rongold
Do you know the casting date? Is it a small journal or large?
Tom

john you read my CE 4N2977 # when i bought mine . small journal forged crank .it is a 3 cast # on block . 1973 not 63 .but still what was needed .

No, I just found the picture on the web.

There is no way to tell small journal from large journal crank w/o removing pan?

There is a book which described the different blocks including the cranks. I remember comparing my block and the crank and found it was a small journal with a 4577 forged crank. The casting date has "B184". So it has to be from Feb 18th 74 correct? On my bock the pad was grounded down during the machining. Though I remember it had CE as the prefix. It does have the breather and a later style oil filter.

Don't give up. I got it!! Even removed the "date correct" after NOM engine in my profile. It just means I'll have to put about another 100k on this engine before looking for another. Sounds like fun! Thanks for the info. :thumbs: Dave

Is this block still available?

Nope, not from GM - it was discontinued over 20 years ago. :thumbs:

Thanks John, but i meant from the O/P....:)

Block
 

I have one of htese blocks. It is complete with a fresh rebuild and was bored .60 over. It has been sitting for a few years so it may need gone through just to be safe.

Years ago I posted here on one of these blocks in my Father's car!
 

Took alot of crap! Thus I feel vindicated by the increase of knowledge about this casting number. It shows in one book as a non-application use, just like a particular 1957 casting that also shows no application (GM racing ban!!!!!!!!!!! Exact same years!!!!!!!!!!!!See the correlation!!!!!!!). Our's came with a GM hybrid cam that came in this block that is a cross between a 30/30 and a 140. It reads very strangely with characteristics of both. The block was cast in 1963 but sold CE stamped in 1969. I am sure that he got it thru Dick Valentine (Corvette Racers)- and a dealership that he either owned or was involved with.

PS my opinion and nothing to back it up, this is a funky block and had some special casting and the vent hole in the back. And I apologize for being stuck on this, but the AMA ban was tightened right in Feb or March I think of 1963. I remember reading that the exotic 377 aluminum engine was already out of the plan for 100 car FIA rule. Thus Zora and gang, not GM were headed toward the 327 size, but with a race appropriate block that could hold up. Thus I believe this block casting was begun, but they only got as far as the block and maybe some Camshaft prototypes. Also to talk to the car, I cannot remember reading anything ever that the 100 Car requirement was going to be built to the same level as the Prototype Grandsports. I would have to look and find the Sebring entry papers or any other FIA sanctioned event to see what was presented to qualify and class the car. Thus theory only, a large number of these blocks were laying around until about 1968/69, someone finally decided to do something with them and they went into the parts counter with CE stampings and could be configured to 2 bolt or 4 bolt mains, thus some additional machine work was probably done to them. But the confusing thing on this most recent thread is that some were cast with a built date into the 1970's. Our engine is definitely early 1963. Thus I am going to post a question asking what cam was in the actual Grandsports.

Hello all,
I am new to this forum, but was wondering if anyone could help me out with determining exactly what GM small block I have.
I have a SB with a casting number of:3959512.
It has a date code casting number of:K68
It has a stamping on the deck of:19N550021 V1I19DZ
This is a 4bolt main engine.
I purchased this bare block around 1979 or 1980 from a guy by the name of Joe Stanislaw(AKA Camaro Joe) in Flint, MI. At that same time I also purchased a crankshaft with a 1178 casting number. At the time I had a 1969 Camaro RS/Z28 that I had intended on installing it in. I never did install in the Camaro and I have since sold the car many years ago, but kept the block and crank.
My intent is to sell the block and crank, but I'm trying to figure out exactly what I have for a block, as the casting numbers do not fall into the normal 1969 302 block numbers, and most references I have seen on the internet show the 3959512 block as 327 being built between 62-63.
Any help or advise would be appreciated.
Thanks

Interesting---It's probably an over the counter engine that was cast on November 6 1968 and stamped with the vin of a 1969 Camaro Z-28--possibly a warranty replacement----BUT, I thought all warranty engines were all stamped "CE".

That's a Service replacement block cast on November 6, 1968, that's been restamped with the Camaro VIN and DZ machine code; the 9512 block wasn't used in production. :thumbs:

TopLS69, could you post up some pictures of this block. If nothing else it would be nice to see one in the flesh so to speak.

Once upon a time I was looking high and low for this 512 block to have my cake and eat it too. Couldn't find one anywhere.

[IMG][IMG][IMG][IMG]http://imageshack.us/photo/my-images/200/2012040.jpg/[/IMG][/IMG][/IMG][/IMG]

that didnt work for some reason...I have no idea why I cant use image shack on this site, but it works everywhere else.... P.M. me and Ill send em your way, or tell me how to post pics on here.

I also have been looking for one.....

Topls69 I get the assist!
you had an extra "/" at the end... here you go
http://imageshack.us/a/img832/2659/2012037.jpg
http://imageshack.us/a/img717/3350/2012035m.jpg
http://imageshack.us/a/img835/4890/2012034.jpg

I don't know if I'd trust these guys to work on my transmission though...
http://imageshack.us/a/img41/9818/010lg.jpg

revfan thanks for the assist!! yeah the last pick is of some of my musky fishing buddies from a tournament, not the guys you want working on your vettes. this block is just as it came from the factory other than i ran it through my shot blaster.

it looks like its plumbed for pcv breather on the back...is that correct?
journal and bore size?

Yes its machined for pcv/road draft. Standard 4.00 bore, large journal. Never blown up or damaged, I'm still deciding what I'm going to do with it.. I have matching heads and a bunch of other parts to put something nice togather with it if I ever get all my big blocks I'm working on done. Probably going to make a nice stroked street motor out of it...someday.

Thank-you guys for the info. Much appreciated.
Anybody interested in the block or crank can email me at: choochoocharlie65@hotmail.com
Scott

Decided I'm not going to do anything with that block.. I just listed it on eBay, just search 3959512.. Low reserve.

hi anyone know the replacement casting number for the 512 block?
the one given by gm..