4 Bolt Block What is it?
 

I have a block, casting #481988, date code B191 that has four (4) bolt mains but there are "no" markings on the front of the block and it has not been cut.

I have been carrying this engine for years (1972) and just broke it down to find a light crank, nodular rods, ram air pistons and 4 bolt mains. Don't have a reference for casting numbers so I need help.

What is it? Thanks, Truman

That number appears on '71-'74 400CI. So a '71 (265-300HP) as per date code.

Any number on the crank?


Numbers can be found at www.wallaceracing.com or http://www.angelfire.com/fl4/pontiac...chineshop.html

May be a candidate for a 1970 RamAir Service Replacement block?
Production years cast number were grinded off and earlier years cast number were stamped at the grinded location and SR number were stamped close to were the VIN used to be....

Truman,

I sold a NOS Service Replacement block and recall reading that some didnt have SR stamped on front and not all had new VIN put back at dealer.

Reading some other posts I recall that some blocks didnt get stamped at all with VIN or block code. I think the ones I was reading about were on 69 model year (on production blocks) .

I know with two CA made 455s I have now, they stamped the block partial VIN off to the left under where the head edge would mount as you are facing the block.
They have a Z in block VIN number for Freemont, CA.

By chance did you look way up to the left? If it didnt have a block VIN/EUN at all it may be a SR that didnt get stamped when installed at dealer (?)

I had a friend who worked at a Pontiac dealership as a mechanic from around 1966 to 1975.

He told me the parts counter kept one or two short block assemblies around for warranty purposes. He said most of the 455s in the early years were all 4-bolt main because there wasn't that big of a difference in price between the 2 and 4-bolt short block assemblies. These were SR blocks, and had the SR number stamped on the front. I believe these were usually short blocks or fitted blocks (no crank).

When a car came in and the short block was replaced, the mechanic was supposed to stamp the code and VIN in the block. I think he said they weren't supposed to stamp the number beneath the engine code because that was used to track engines built by the factory. He said it was hit or miss whether the person installing hte replacement block stamped any numbers.

My friend said anyone could order a new 4-bolt main 400 or 455 bare block. These had no number on the front, nor did they have the SR number.

He also told me that he installed a SD455 short block into a station wagon around 1974. He said an influential customer came in with a engine problem just before he was leaving on a trip. The only 455 short block they had was a SD455 short block that had been ordered by one of the mechanics who raced. They installed that block assembly and the guy ordered another one.

I don't know if it was true or he was exaggerating, but the guy had a bunch of neat hi-po parts. I picked up several tripowers, 428s, and a YE and XF 455 4-bolt main from him. He said the mechanics would try to snag any 4-bolt short block that was swapped out under warranty for later use by somebody who raced.

Mike

Gentleman - Put on your Thinking Caps Please
 

I am beginning to believe that this is a 1970 (B191) Ram Air 4 block (SR) from engineering that has never had any info stamped on the front of the block. That being the case, what is it worth?

Back in the 80-90's, GM would send us notices of pending disc. part #'s.
I grabed the last 11 400 bare blocks for $75 ea!
Were the 557's. Had no letter codes or #'s on the front.
There were no X7's or any other HD castings. They were long gone.

Another note;
When i took over as parts manager in a Pontiac dealership(84), i found a listing for all the replacement part #'s for the 68 RAII engine in the old mgr's desk.

Just think if i was older and worked there during the 60-70's.
I'd be rich now ;)

Not sure, but i would think alot to someone who had an original car without the correct engine, and coul'nt find one with correct letter code. And if they did, the vin # would be wrong any how.
They could stamp it themselves, and no one would know the diff.

Worth at least a million!

Truman

Weren't you friends with Tom Nell and got special things from Engineering? If this block is one of those things; which I'm guessing it is since you don't have any stampings on the timing face, it could be something besides SR.

Most SR's have "SR" stamped if I'm not mistaken. Although you block is not the same casting as the 70 V's 481708, I'm curious if you would know the difference in the lifter valley between a regular block and the V?

I know this is a long shot, but thought I would throw it at you.

Thanks for everyone's input..
 

Steve, you are correct as to where this came from but the lifter galley is normal, no cross bracing.

As for "worth a million", I wish.... Guess I am going to sell this complete short block as a SR replacement for a 1970 RA4 car, date code B191..

Asking price of $5K - OBO Thanks gentlemen..

Truman, don't sell it. It should mean more to you than anyone else, once it's gone it will probably never return.

If you went down to Pontiac and bought a bare 4-bolt block brand new over the counter, it did not have a SR number or any number. They only got coded if you bought a complete motor.

Mike

I posted this in the other thread too.......
 

My 1970 400 SR block cast in 1971 have 2 bolt main caps, though it´s drilled for 4 bolt caps.
Therefore, not ALL 400 SR blocks got 4 bolt caps.

1971-72 455 H.O.´s also got 4 bolt main caps.
A 455 SR block with 4 bolt main caps and a 1973 casting date may very well replace one of those.

From 1971 MPC:

BLOCK ASSEMBLY, ENGINE CYLINDER.
Blocks are fitted with pistons, pins and rings.

70 All 400 exc. Ram Air part-#479877 1 $ 295.00 BLOCK

70 All Ram Air III part-#479878 1 $ 350.00 BLOCK (w/YZ or WS eng.)

70 All Ram Air IV part-#479879 1 $384.00 BLOCK (w/XP or WW eng.)

Based on prices for these SR blocks, i would say that it´s safe to sum up this as:

A 400 SR block for std applications got cast pistons and 2 bolt main caps.
A 400 SR block for RAIII applications got cast pistons and 4 bolt main caps.
A 400 SR block for RAIV applications got forged pistons an 4 bolt main caps.

A note, 1969 SR 400 Ram Air III or H.O blocks got 2 bolt main caps.

Truman

I'm curious how you got the block. Did you pick it up at engineering, shipped direct to you, or pick it up at your local dealership? And is it as is Tom built it for you, or did he just hook you up with the bare block?

How Did Part Come To Me?
 

Well, After Indy Nats in late 1971 when MotorWheel & Kenner Toy bought the SS/K 1972 455 HO 4spd car for me, Pontiac provided all the necessary engines/SD rods/transmissions/rear ends/etc and all of the product sponsors (Crane/GoodYear/Gasket/STP/Valvoline/Lunati/etc) provided everything else necessary to run a good program.

In the first shipment from Pontiac there were 6 complete assembled 455 HO engines, 6 rear ends, 6 transmissions, and considering that I would still be running the 68 Bird in Stock, there were a couple of 400s and sets of RA96 heads. I am probably forgetting something but that is how my 1972 season began.

When I received the 72 GTO and immediately began stripping it, my Dad went nuts, "when are you going to quit this kid ****", well Dad, I know you are still watching me and I haven't quit yet..

If someone could find my 72 GTO I would sure like that one back - it had less than a 100 miles on it. Last I heard it was in Iowa, but can't confirm that.

Thanks guys...

1972 GTO HO 455 Ram Air 4spd
 

Anyone find my car???

Truman, was your car white?

[QUOTE=Hard-Timess]Well, After Indy Nats in late 1971 when MotorWheel & Kenner Toy bought the SS/K 1972 455 HO 4spd car for me, Pontiac provided all the necessary engines/SD rods/transmissions/rear ends/etc and all of the product sponsors (Crane/GoodYear/Gasket/STP/Valvoline/Lunati/etc) provided everything else necessary to run a good program.

In the first shipment from Pontiac there were 6 complete assembled 455 HO engines, 6 rear ends, 6 transmissions, and considering that I would still be running the 68 Bird in Stock, there were a couple of 400s and sets of RA96 heads. I am probably forgetting something but that is how my 1972 season began.
[quote]

Holly crap!
Life must of been great back then.

I knew where it was then. And now, but Truman. Thankfully, you also know where it is. Now!!!

I have a 4 bolt block that came in a 1969 Grand Prix I once had. The block casting number on the back of the block was partially ground off and restamped. I seem to remember an article in the past talking about blocks that had this treatment referred to "H'ot Wiping" done to the cast #. Can anyone here provide any information about this? How and Why was it done?

Are you talking about a 400 block and can you let me know the number that was cast and stamped also the date would also help

Yes I believe it's a 400 block,. XH code. Stamped # looks like 9790071. Date CO39. It came in a 1969 Grand Prix.

From what I recall reading, prior to the end of the 1970 model year, the casting number was either partially, or fully removed for the ‘915, or SR for earlier castings.
It seems as though after the end of the 19670 model year, the block casting number was left as-is, and the block was just finished as required.

I looked at Wallace Racing and the casting # for 1969 GP XH 400 was listed there as 7029268.
I did some more research and found this site; https://wowmusclecars.com/pontiac-engine-codes-specs/
There I found "1969 400 XH 9790071 4 Bar Carb 350HP Grand Prix" . just what is stamped on my blpck.
I can't tell what was ground off, but a 4 bolt main 400 that came in a 1969 Grand Prix . OK

The 7029268 is the carburetor number.

The 9790071 would be the 1969 block code, possibly they had a 9799914 which were starting to be used in 1969 Firebirds mainly because of the extended year for them. They probably 'wiped' it and stamped the 9790071 into it.

Does the block have 2 engine mount holes or 5?

:)

The block has two engine mount holes per side.

I just noticed a tiny, but huge typo, that makes my post almost seem gibberish with just one extra charecter...

Fixed.

I would be incline to agree with John's post;
I have observed that regardless of casting number, the date code is generally present, and can be used as an indicator of when that block was made (eg: which block casting was being used at the time).

So as it was cast March 1969, the 4 bolt block casting for that time would have been 9792506 for RA III or RA IV stick or A/T application.
So could this have been a service replacement upgrade done at a dealer? Or a substitution done at the factory?

With the engine unit number and engine code, it would be done at the factory. Possibly the original was messed up and they set it off line for another engine to put in?


:confused:

I had thought that prior to 1970, service replacement blocks were cast and prepped (along with being renumbered) for their intended application;
eg: a car with an original 9790071 cast block, would receive a replacement block with the same number.

With that being said, according to my Pete McCarthy “bible”, the 9790071 block was a 1968/1969 two bolt main block casting number, so my initial thoughts were that the block being renumbered meant that it was an SR block intended for 1968/1969 application;
Again according to the “bible”, XH was a 1968 & 1969 full sized/G.P. 400/4bbl-350hp motor.

I think that it might be prudent to take pause and question weather the Pontiac foundry swapped over to the 1970 castings by March 1969 - the block being drilled and tapped for four bolt mains might seem to suggest this.
OR(!)
maybe the early motor mount bosses would suggest this was cast prior to the 1970 change over.
I am thinking now that this block was originally created as a 9792506 casting, but supply demanded that it be renumbered and used as a non-RA engine…

Does the block code ect. look legit?
Does the block have the G.P.’s partial vin on it?

The stampings; EUN, engine code, and partial VIN all look like legit Pontiac font and size stamps. The hot wipe of the cast block part number, and subsequent re-stamp makes this block's origin the mystery.

Dealer replacement with upgrade to 4 bolt mains ?

I almost want to get the PHS for the car it was in, to check if the EUN on the block matches the " as built with" EUN on the billing history.

If they are the same, then it would have been a factory substitution

If non matching EUN, then a dealer SR block.

Assuming every block was assigned it's own EUN, whether going into a car on the line, or going into inventory as stock for OTC or SR sales. with the other identifying stamps to be done by the installer.

So OTC blocks may have no code or VIN stamp, but dealer installed would get legit Pontiac font re-stamp? And maybe a hot wipe and a block # re-stamp.

If the stampings look legit, I’d really be curious to hear the thoughts from someone authoritative on this.

An XH block used in either the 1968 or 1969 model year should be a 9790071 block.

If I have this straight, the 1967-1968 RAI block used a 2-bolt engine with cast slugs just like everything else made before the introduction of the ‘2506 block with the RAII;
That is to say that all 1968, and 1969 D-port 400’s would have used the 9790071 short block assembly.

Only the 1968.5 RAII & 1969 RAIV used the 9792506 casting, which was finished with four bolt mains, and assembled with forged (TRW) slugs.

With a change in how PMD was dealing with substitution or SR short blocks starting around 1970, it would not seem to be a stretch to think that a ‘2506 casting could have been put in service as a ‘0071 block…

The difference between 1969 & 1970 was that for 1969 only ‘2506 blocks were drilled and tapped for four bolt mains - while for 1970, the few 400’s NOT drilled and tapped are the oddities.

Could PMD have started substituting blocks assemblies before 1970?

I think it’s quite feasible.

If PMD did substitute, would the casting number have been wiped?

I think that everything I have learned of PMD’s practices would suggest that prior to 1970 the number of the block was of upmost importance..

I believe the EUN was used for warranty purposes, and would not have ever been stamped on an OTC sale….
but I am a little muddy on precisely when or where the EUN was stamped.

It would be great if someone documented this kind of stuff for people like me who were born too late ;)