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My 67 gto has a date stamp on the motor as "K146" and a block casting code of 481988. It looks like these two numbers can't be on the same motor. Can anyone explain this? Thanks.
 

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the gm block casting # 481988 was used on 400 engines from '67 -'78. you gotta have the the 2 letter code up front n casting date to ID a Pontiac engine.
 

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the gm block casting # 481988 was used on 400 engines from '67 -'78. you gotta have the the 2 letter code up front n casting date to ID a Pontiac engine.
That's a stretch, the 481988 casting 400 block was first cast in early July of '70, for '71 model use. the 481988 casting 400 block was cast for use into the early into the '75 model year, then its use was discontinued, replaced by 500557 400 (thin main webbing) block.

For the '78 model W72 400 blocks, code X7 and WC, the 481988 casting block again began being cast in the late summer of '77. This time it had an XX casting in the valley area, and only 3 bolt bosses tapped for clamshell enginge mounts brackets. The casting of the W72 blocks continued for several months up into April of '78. The Pwh coded 400 4spd blocks for '79 400 4spd T/A's and Formulas also used the Late casting version of the 481988 blocks. Every Pwh block I've owned has been cast in late Sept or Oct of '77, which jives with them being stockpiled for '79 usage.
 

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That's a stretch, the 481988 casting 400 block was first cast in early July of '70, for '71 model use. the 481988 casting 400 block was cast for use into the early into the '75 model year, then its use was discontinued, replaced by 500557 400 (thin main webbing) block.

For the '78 model W72 400 blocks, code X7 and WC, the 481988 casting block again began being cast in the late summer of '77. This time it had an XX casting in the valley area, and only 3 bolt bosses tapped for clamshell enginge mounts brackets. The casting of the W72 blocks continued for several months up into April of '78. The Pwh coded 400 4spd blocks for '79 400 4spd T/A's and Formulas also used the Late casting version of the 481988 blocks. Every Pwh block I've owned has been cast in late Sept or Oct of '77, which jives with them being stockpiled for '79 usage.
that's what my cylinder head/block ID guide says. AUTOMOTIVE ENGINE REBUILDERS ASSOCIATION. COPYWRITE AERA 1981. I worked at a auto parts store / machine shop in the mid. '70s. this book was our bible for identifying heads n blocks for ANY American engine, not just Pontiac. I looked in another old book I have n it says not till '71 like you said.
 

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It's perfectly clear. I have a good photo of it. I wondered if it could be 1976 instead of 1966, but that don't make any sense either.
 

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can you make sense out of my date stamp?
As mentioned, all 400 blocks used in '76 and and '77 were 557 blocks, including the '77 W72 engines. So, I can't see any 481988 blocks being cast in '76. Then, as mentioned, the '78 & '79 W72 engines used the XX481988 blocks, with only 3 motor mount bolt holes. All the date codes on these blocks, which I've seen are from '77. I've read that no Pontiac 400 blocks were cast after '77. Can not confirm. But I've never read of anybody who has seen a 400 with a '78 date code.

If all this is true, then the only thing that remains is that whoever set the date code numbers which were cast into your block just simply used the wrong last number--a simple mistake. There were a lot of those on the auto assembly lines. I've read about all sorts of stuff that did not come off the assembly line as it was supposed to. Hey, people are human and make mistakes.

By the way, what is the 2 digit code, off the front of the block ?
 

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Mike, the following are "5 bolt" engine mtg bracket 400 blocks, first introduced lfor the '70 model. earlier 400 blocks had their own casting number AND only had provisions for two bolt engine mounts.

#979914 '70 model 400, both 2 bolt and 4bolt main caps (4 bolt is typically RAIII,mthough a few '70 WT 400's have surfaced w factory 4 bolt caps

#979915 or 97991(5) '70 RAIV, but a few '70 WS RAIII also used his casting
*the last digit, 4, was wiped and the proper font large 5 was stamped.

#481988. First cast for '71 400 usage but continued on into early '75 model production. The complete application of the 481888 block is exactly as I mentioned above. Throughmy specialty core business I provided select 400 shortblock cores along with 6X-4 head cores for many years to a major national Pontiac engine builder. I seriously doubt anyone on his forum has had as many 400 Pontiac cores go through his hands.

#500557 Partial '75 usage, then into '76 model.
During the'76 model year, the 5 bolt mtg boss arrangement on side of the block stopped and the late style 3 mounting boss block began. Crank register size (for the flywheel) changed from 2.75" to 2.5" as well.


Checked my engine code/ build database, the following is the earliast 481988 casting 400 have run across. Note block cast July 1st, 1970.

(004541......YS........G010.......08D.....276571A100529....400 Grand Prix (Paul's farmer yard)

The above pertinent info is from an extremely early '71 build from the Lakewood GA plant.
The VINs of T-37's, LeMans, GTO's, as well GrandPrixs all were intermixed at the plant as far as the sequential last 6 digits go, the preceding and following VIN could be another GP or a Pontiac A-body.
 

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Don, I've personally owned a feb of '78 dated X7 block with early April of '78 dated 6X-4 heads. Have had several X7's and currently have two WC's, along with all the junk '78 Bonneville coded 400 blocks have never had another '78 400 block cast that late.

All the production '77 400 blocks had 3 mtg bolt bosses. The mtg boss change was during the '76 model year. When I was pulling 400 cores on a regular basis, I used to look real close at the block casting dates, as the main reason I ever pulled the generic 400 code 500577 blocks was for good cranks (one that would turn no more than 10-20) hardware, oilpans, and timing covers.
 

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OK, that makes one person I've heard of that has ever seen a '78 cast 400 block. You've probably seen a lot of stuff nobody else has seen.

What about the 568557 blocks. Have you seen a lot of those ? I see 'em listed, but have never even seen a picture of one. Some sites show 'em from '77-'79. But I thought the only 400's in '79 were the W72's. Anyhow, does that mean that all non W72 '78 400's used the 568557 block ?

Here's one of those sites that says the last blocks were cast in '77.

http://www.bandittransamclub.com/The_Last_Trans_Am_Engine.htm

Rocky Rotella says the last 400 blocks were cast Thanksgiving weekend '77. I don't have a clue.

https://books.google.com/books?id=iBPFB0nDuEwC&pg=PA14&lpg=PA14&dq=were+any+pontiac+400+blocks+cast+in+1978&source=bl&ots=SYwKRW4Fd5&sig=qR5U8y2gJErmgW6s3NPIRTzvTtY&hl=en&sa=X&ved=0CCoQ6AEwAmoVChMIx9zQ-eCxxwIVRBaSCh33rgUa#v=onepage&q=were any pontiac 400 blocks cast in 1978&f=false
 

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Don, it's been at least a dozen years since I tore down a '78 400 Bonne engine. i never liked that particular core, and do believe the casting number was different. With the 557 at the end of the casting number I never gaveit much attention, just knew it had the thin mains, and on those I couldnt sell the block in the longblock deal, so was just after the crank, hardware, oilpan on a '78 Bonhe 400. Seldom even needed the 6x-8 heads. Rocky and I use to share a lot, I don't remember conversing with him on this particular X7 block. Will find and go through my old receipt pads, and find the block date and assembly number. Have always wrote the dates, block code, and assembly number down. Thought that X7 was odd when I pulled it, as I was needing a pair of Jxx7 dated 6x-4's for a Pwh I picked up with 15 heads, the heads from the X7 were dated real late, I ended p having them for years, , and I was like Hmmmm, what do I have here?

Pulling Pontiac 400's, for over a decade, I had deals with the owners of several crusher yards and the mgrs of three Pick-N-Pulls, all for Pontiac 400 longblocks. Its not like the smog era 400's would sell like an 010 4bolt SBC. The yard help could even set the cars in the Pick-N-Pulls, and I'd be out of town on the road, come back in town, and maybe an HEI had been pulled, that's it. Usually the smog era 400's would just set there, just like the 301's...and get rained in :( At one Pick-N-Pull, I hit it at least once a week, the entire Pontiac section would crush row by row in 6-7 weeks where as the Chevy section only crushed twice a year. Beginning in '89 the mgr of the big hometown Pick-N-pull let me pull any Pontiac engine at a whls agreed price, the day the cars were set. One other Pick-N-Pull had the same owners, and eventually I got the same deal. Pulled every set of 6x-4's and 96's that made it into these yards and all went out with a 400 shortblock.

Eventually, the cars I was pulling 400 shortblocks out of quit coming in, more and more front wheel drive junk... If a Pontiac 400 did come in, the last few I pulled had spun rod bearings. I hit about 4 of those bad crank deals in a row at local Pick-N -Pull, and the counter help began to give me a hard time about what was our warranty deal. Ever since the beginning, our whls price was with a crank that could turn, not scrap. I just said its over, it was great pickings while it lasted! Since the Pick -N-Pulls died out, the only Pontiac cores I've pulled have been from own partscars and from several country yards.
 

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6x-8

"...Seldom even needed the 6x-8 heads..."



I assume that those 6x-8 heads are more valuable now, for the pump gas stroker engines, than back when you were working the yards ?

I run across guys quite often who need some good 6x-8 cores and 481988 blocks, for a mild stroker build. Do you sell any of these nowadays, to individuals, or just builders only.

If not, could you give me the name of guys who do often have these for sale. Thanks. :)

Also, just as a side observation, I would assume that because of all the stroker builds, there should be plenty of 400 crank cores available, dirt cheap ?

It's ancient history, now. But I had a deal with a scrap dealer. I could buy all the Pontiacs engines for $50 a pop. And I think the TH400's were $25. Hey, back then, I was only interested in 455's and the high compression 400 heads. I didn't know anything about the 481988 blocks. To me, they were just low comp smog motors. Not worth pulling. This was before the days of the cheap Chinese stroker parts. Most of the 455's were in Grandvilles. And most of the heads and short tail TH400's were in '69-'70 GP's.
 

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With 481988 block casting and an original stamped WS above the assembly number, the block is going to be from one of the following engines:

- '72 400, originally built with 7K3 heads and 4bbl intake. Originally installed with HD Muncie 3spd trans applications in 400 4bbl LeMans (with or w/o the GTO option)

- '73 400.....again a base 3spd 400 4bbl application engine.
This partial model year, came with 4X 7h screw in stud heads. The 73 WS was for A body use, and for use in '73 Formulas with 400's and manual 3spd.

Below the WS (two letter ID code), there is the assembly number, this 6 digit number will start with a left hand parenthesis mark ( for all production '71 -74 Pontiac V8 engines (only exception being the '73 and '74 455 SD blocks $$$$$)
 

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The WS code was reserved during product planning in the winter of '69-70 for a 400 2bbl engine for a '71 model B series with manual trans, but the powertrain combination was cancelled and none were built.

Likewise, a good 8 months before production, the WG and WJ codes were also reserved for '71 455 Dport manual transmission engines for the '71 B series, but those too never made it to production.

When '71 B series pruction actually commenced, there was only one manual transmission choice avail on the Catalina and that was a Pontiac 350 2bbl with Saginaw 3spd and three on the tree... no floor shift option, no 400 or 455 manual transmission options in a '71 B series.
 

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Pinion head. Online info shows that the WS code was used on A, B, & F-body '71's.

So, what you are saying is that all this info is incorrect ?

Is there an online link to all this inside info you come up with. If so, please share that link, or links. Your sources obviously have a lot of info that MOST of the online sources do not have. I'd like to be able to give guys accurate info, on some of these other Pontiac sites. I hate to give out bad info. :(
 
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