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Discussion Starter #1
I have a 64 GTO and I located a stamp on the lower right side of the block behind the lower rad hose and it reads "SR8 1265" and the casting code is 9773155. I found the casting code is for the 389 but I can't figure out what the stamped numbers mean. Any ideas?
 

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SR I believe indicates "Service Replacement" --- meaning the block isn't the one the car was born with but was probably replaced, perhaps under warranty, when the car was still pretty new. Can you read the 4-character date code on the top rear near the distributor?

Bear
 

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I believe the SR8 1265 means it was a service replacement under warranty in December of '65.
 

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Discussion Starter #5
Thanks for the quick response. My bad as you can see in the pic it's 1256 not 1265 as for the casting # it is 9773155 and next are 3 numbers "084". This car was purchased off the show room by my step mom and my brother is the only other owner and neither one of them had the engine replaced which is puzzling. I wonder if the dealer had to replace it before selling it new. Thanks again for your help
 

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Cruising some old threads and found this one. I feel compelled to reply because there is bad info it. Some of the info is 100% incorrect

9773155 is a correct engine cast code for a 1964 GTO no matter is it is tripower, 4 barrel carb, auto or man transmission.

76W A-body 64 389 348 4-speed 3x2 9773155 2 GTO
76X A-body 64 389 348 3-speed 3x2 9773155 2 GTO
77J A-body 64 389 348 Powerglide 3x2 9773155 2 GTO
78W A-body 64 389 325 4-speed 1x4 9773155 2 GTO
78X A-body 64 389 325 3-speed 1x4 9773155 2 GTO
79J A-body 64 389 325 Powerglide 1x4 9773155 2 GTO
769 A-body 64 389 348 4-speed 3x2 9773155 2 GTO
789 A-body 64 389 325 4-speed 1x4 9773155 2 GTO

The correct cast number is on that block for that car.
SR is a service replacement block. The numbers after sr are supposed to be the either the partial vin or full vin of the vehicle that were supposed to be stamped onto the block by the dealer replacing the block. But this was not always done.

084 kinda looks like a date code but I can not be certain. It might be Aug of 64. It would help to know the vin of your vehicle and the build date. If the build date is after Aug of 64 the theory is out the window. But look at the vin of your vehicle and see if it matches the numbers after the sr. But hat cast code is correct for that vehicle.
 
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