SR Service replacement block number
 

I was wondering if anyone knows what the numbers after the "SR" stamped on the front of the block mean? a part number? or just a casting sequence number?, I know its not the casting date or block casting number as they are in the normal locations

Can you post those numbers and the block casting number and date?

Also is it a 3 inch or 3.250" main Bore?

I’ve been recording SR block numbers for quite so time. What I can say is that they seem to jump around. They all start with “SR8” which is followed by four or five digits.

The “SR” stands for Service Replacement. The “8” signifies 8 cylinder (A “6” was used in this place on OHC-6 engines). And the numeric sequence was the engine serial number. At first I thought the serial numbers were sequential, but I don’t believe that to be true any longer. They’re generally 10,000 or less.

It’s interesting to note that SR blocks were sold as a “fitted assembly.” That means a machined block with main caps and pistons/wrist pins.

Can you share your numbers?

here' s the pics 62 389 block

Can you post up a picture of either side of the block back by the bell housing flange?

Does the block have a reinforcement wing cast in from the lower side of the rear deck to the bell flange?

Were the SR blocks made from stronger castings or the lightened 557 castings?

Here are some pics of my 455 4 bolt main SR block.
SR8 1758

For Rocky

The guy I bought it from installed an NOS SD crank and TRW forged pistons. And topped it off with 455 SD heads.
I don't have the heads.

yes it has them

Then that is a casting of the 325A trophy block that was used for both 389 and 421 motors.

Most are far stronger than the 557 blocks. In this case, it is a VERY strong block.

this thread might also be of some assistance:

https://forums.maxperformanceinc.com...d.php?t=826840

Thank you!

Thank you!

Do you happen to know if it has 4 bolt main caps?

And as a note to all following this thread, my comment earlier about SR block number sequencing is visible here.

Pont406's SR block (cast Jan 16 1962) is numbered "1967" while Old Goat Racer's 455 (cast Oct 11, 1972) is numbered "1758".

I'm trying to determine how Pontiac decided upon their numbering system.

have a 428 4bolt SR in the rack, will get you the number Rocky.

Thanks, Roger.

If you're able to snap a pic of the casting number, cast date, and SR stamping, I'd love to add them to my info. Also, if possible, can you tell me if it's two-bolt or four-bolt main caps?

YES it does.

Rock, it's a 4 bolt, will take some pics.


Most SR 400's were the thicker web earlier block castings. that stated, 500557 casting SR 400 fitted blocks were built. Picked up a 557 SR fitted block many years ago, ended up using it in a '77 Y81 project.

Thank you. I'm finding that all SR 455s from the 72-74 era were equipped with 4-bolt main caps.

My block is also 4 bolt main

Rocky, would this mean these SR 455 4 bolt main are 455 HO service replacement blocks ?

Technically, yes, but because the '71-72 455 H.O. shared the same short block with the standard 71-74 455, there really isn't anything unique about the 71-72 455 H.O. beyond its four-bolt main caps. Basically, if you were warrantied (or purchased) an SR 455 during the early '70s, the SR fitted assembly you received was equipped with four-bolt main caps regardless of whether the original application was a 455 H.O. or low-rpm 455 two-barrel. And that would apply to other sized SR blocks produced during certain years like the 389, 421, and 428.

Not sure if these pictures help you or not Rocky, but here is what I have on a 69 RAIV SR block.

Thanks! Do you happen to know the date code on the block?

Sorry that I left out the date code.
It is B212.

Thanks!

Rocky,
Here is my entry.
73 455 SR Short block.
The numbers on the front of the block are :
SR 82448

And by the distributor:
K263

Rocky

I dont have a picture on my computer, but here are the numbers of my 70 ram air 4 replacement block.

stamp on the back of the block is 9799915 original casting number is ground off and this number is stamped over it.

the SR # is SR87328
it was cast E262, May 26 1972
it had a 9794054 crank, super duty rods and 722 X heads on it

I have a 455 SR engine that is dated from 1973 that was bought in the 1980s sometime.

Thanks for the info, guys.

If there's anyway you can send photos of the SR number, the casting date, and the casting number/stamping, I'd appreciate it. Also, if the pan is off, I'd like to see the main cap numbers.

Here's the stamp and SR#https://uploads.tapatalk-cdn.com/202...dc561a359f.jpghttps://uploads.tapatalk-cdn.com/202...88c597d303.jpghttps://uploads.tapatalk-cdn.com/202...7c3d7fe5ce.jpg

Sent from my SM-G973U using Tapatalk

Thank you, moparcolt!

Rocky, I sent you a PM about another one

Sent from my SM-G973U using Tapatalk

Thank you!

70 SR 400
 

This one 70 SR 400 block is SR81318 and is a #9799914 cast with an early build. Maybe an H or I of 69 date.code? Will check exact date later for you.

Thank you, John. Any pictures you can post or send of the casting number (or stamp), SR number, and cast date would be a help so I can photo-document it in my files.

Rocky,

Here are some numbers as I have been trying to do some research for a replacement of my 64 389 76x block which is not repairable

these are from Ebay (still there)
9792506 built A229 SR82002 4bolt block number ground then stamped

9799914 built F071 SR812192 4bolt block number ground then stamped

50081 built B256 SR89716 455 2bolt cast part number

will need to get the numbers off my 64 389 SR Block that I found when I get back from machine shop

As far as I know there where no 4 bolt 389 blocks in 64 and up thru the last in 66.

Yes you are correct, just sharing info with Rocky for his research, these are 400 sr blocks and 1 455

SR 87852 400ci 9790071 hand stamped….casting date ‘71