[steve25]

Could that 85650 number have anything to do in relation to the 87684 GTOs that where made in that model year?

[Rocky Rotella]

Originally Posted by grandam1979

Just got another 400 SR block SR811992 D201 that’s 6342 higher than the other one cast 1 year earlier D100 not sure it means anything but just over 6000 service blocks would seem about right in a year. I’m wondering if the engine size was a factor in the numbers on block?

Grandam1979, can you attach some pictures of the new SR block? And are the numbers cast or stamped? I'd love to add them to my collection.

Concerning the numbers, as Johnta1 pointed out, I've been tracking SR blocks for years. While they're certainly not rare, there aren't as many out there as people might expect.

What I can tell you is that I can no correlation to the sequence following "SR8" (which signified Service Replacement 8-cylinder). Most are higher than those produced during the preceding calendar year, but some are lower. Some produced in the same model year may be 10,000 units off. I don't know that Pontiac kept any specific record of them.

I supposed the bigger question is, how many warranty failures did Pontiac have that required a new fitted block (block, main caps, and pistons) each year? If I had to guess, I'd say it's a relatively low number. And combine that with the sheer number of fitted blocks Pontiac sold over the parts counter to racers, the SR blocks that are out there, not all were destined for warranty repair.

If anyone has any other insight on the sequencing (or paperwork that clarifies it), I'd be interested in learning more!

[grandam1979]

Pictures,

[Tellyshavilli]

On the service replacement (9792506 ) 400 ra blocks the factory ground off one of the engine mount bosses so that would not be able to be used in a 70 up application very strange but I’ve seen many like this

[grandam1979]

Originally Posted by Tellyshavilli

On the service replacement (9792506 ) 400 ra blocks the factory ground off one of the engine mount bosses so that would not be able to be used in a 70 up application very strange but I’ve seen many like this

This block has one removed

[Tom Vaught]

Originally Posted by Rocky Rotella

I supposed the bigger question is, how many warranty failures did Pontiac have that required a new fitted block (block, main caps, and pistons) each year? If I had to guess, I'd say it's a relatively low number. And combine that with the sheer number of fitted blocks Pontiac sold over the parts counter to racers, the SR blocks that are out there, not all were destined for warranty repair.
I

All I know is I replaced two of them in early 1970 that were 1969 RA-IV 400 engines.
In both cases the block was changed as well as related required parts. Both engines in my opinion were abused prior to the failures.

Tom V.

[Rocky Rotella]

Originally Posted by grandam1979

This block has one removed

Thank you!

Would you mind posting a picture of that too?

[tom s]

Rocky,as I remember(kind of).When we ordered a over the counter block in the early 60s it was a bare block.Are not SR blocks a fitted block with pistons?Tom

[Rocky Rotella]

Tom,

As I understand it (and Nunzi recalled it this way, too), Pontiac didn't sell bare blocks via the parts counter. The SR assemblies were always fitted blocks, which included main caps, cam bearings, and pistons with wrist pins and rings. Was it possible that Pontiac offered something different in the early years? That may be, but I can't recall ever seeing a part number for such in the parts catalog for any year. Obviously, back-doored stuff notwithstanding.

[grandam1979]

Pictures

[Dragncar]

Originally Posted by Rocky Rotella

Grandam1979, can you attach some pictures of the new SR block? And are the numbers cast or stamped? I'd love to add them to my collection.

Concerning the numbers, as Johnta1 pointed out, I've been tracking SR blocks for years. While they're certainly not rare, there aren't as many out there as people might expect.

What I can tell you is that I can no correlation to the sequence following "SR8" (which signified Service Replacement 8-cylinder). Most are higher than those produced during the preceding calendar year, but some are lower. Some produced in the same model year may be 10,000 units off. I don't know that Pontiac kept any specific record of them.

I supposed the bigger question is, how many warranty failures did Pontiac have that required a new fitted block (block, main caps, and pistons) each year? If I had to guess, I'd say it's a relatively low number. And combine that with the sheer number of fitted blocks Pontiac sold over the parts counter to racers, the SR blocks that are out there, not all were destined for warranty repair.

If anyone has any other insight on the sequencing (or paperwork that clarifies it), I'd be interested in learning more!

Whitmore told me the 1970 10-1 455 with 64 heads ( I have one) had a fair amount of comebacks due to people not running premium fuel. It had cast pistons and they cracked and took out a few engines. He was a dealer mechanic back in the day.

[Rocky Rotella]

Thanks for the pics! Can you confirm these are of the 9790071 or 9792506 block?

[Rocky Rotella]

Originally Posted by Dragncar

Whitmore told me the 1970 10-1 455 with 64 heads ( I have one) had a fair amount of comebacks due to people not running premium fuel. It had cast pistons and they cracked and took out a few engines. He was a dealer mechanic back in the day.

Thanks, I could certainly see that happening.

The question is, did Pontiac ship 10,000 (or more) SR blocks each year? Or were SR numbers picked at random. I just don't know at this point. But I'll keep looking!

[grandam1979]

071 block

[TRADERMIKE 2012]

MIKES Question IS: 9790071 casting, # "979" IS keeping with in THE SERIES OF ALL THE BLOCKS- CAST, "00" IS 400, "NOT" WRITTEN ON THE INSIDE NOR the OUTSIDE of THE BLOCKS AND 71 IS 1971. This SEEMS A LOGICAL WAY that THE factory could DEPICT THE SERVICE BLOCK in order to differentiate them from the originals?



Sent from my XT1585 using Tapa talk [/QUOTE]

[Joe's Garage]

9790 is the first four digits of all CASTING numbers assigned to CAST IRON parts in 1968.

The 071 is just the rest of the original 400 CID block part number.

That's it. Nothing special.

[steve25]

Can anyone who has a old GM parts book please list the part numbers for the service replacement fitted blocks in terms of the 68 RAII and then the 69 and 70 RA4 , because these 3 fitted blocks should have the TRW forged pistons unlike the 400 motors that what we now call the RAIII motors.

Thanks in advance!

[TRADERMIKE 2012]

Originally Posted by Rocky Rotella

Thanks, I could certainly see that happening.

The question is, did Pontiac ship 10,000 (or more) SR blocks each year? Or were SR numbers picked at random. I just don't know at this point. But I'll keep looking!

Mike would like to know: Did the 455 ci or SD use a 60-80 psi pump spring that was problematic 1n the early 1970's that a mechanic helped the factory in testing and development due to a spring pressure issue, causing those Engines to fail early? " Not" the fuel being the actual cause of failure on those 455 ci Blocks.

[tom s]

only engines that used the 80lb pump was 455SD and RA Vs.They also used a larger dist gear requiring a larger dist hole.VERY EZ to tell a SD or V block from a distance.Tom.Tom

[TRADERMIKE 2012]

Mikes Question is: In creating a 389-400 ci Replacement Block "Did the Pontiac Factory use one of the original 1968 Plugs to form a Cast in the manufacturing of this 1970 Replacement Block in this Post, so that the completed Cast is both new and as original as it could be?" I ask this because I see 68 Cast into the top of the Block near the Dist. hole and the cast date depicts 1970.