Stage 2 block, 197????

750H.P.V6

Brutal 6 Racing
Here's my speculation in regard to the block which has 0198U1283 written on it in paint pen. It most likely is the first 197 cast block. The 0198 is January of 1998 and the digits following the "U" are a sequential number from Uni Boring who did the machine work on these blocks for GM. They probably used the machining program they had from the 153 block casting for the first one which is why it is 1283. When other 197 blocks came thru their shop they likely started at 001 and continued. We'll never know for sure, Uni Boring went bankrupt at some point around 2008.

Neal
 

Mike T

Well-Known Member
That sounds very likely. I found the old thread you were looking for and what you're saying aligns with the timeline of production. Last blocks were produced in 99
 

750H.P.V6

Brutal 6 Racing
Mike,

Can you post a link to the thread with the info about the Uni Bore stamp #'s? I still cant find it.

Thanks

Neal
 

Mike T

Well-Known Member
Pretty sure this is the thread you are looking for. I actually started it trying to get an idea of how many blocks were made.
Earlier in the thread I had stated that the U designation was associated with NASCAR blocks only and that isn't correct. A friend filled me in on uni-bore and I had to elaborate on that statement.

Also I believe a member did reply with the numbers on his 153 with all 4 cross bolted mains



 

rag231

Well-Known Member
I have one of those blue stage 2 blocks. I have a cross bolted front and rear main block and I have a cross front and rear bolted main with 6 bolt center caps also.
 

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rag231

Well-Known Member
Maybe they came from the same location. It keeps telling me that my pics of my other blocks file is too large 😳.
 

750H.P.V6

Brutal 6 Racing
Pretty sure this is the thread you are looking for. I actually started it trying to get an idea of how many blocks were made.
Earlier in the thread I had stated that the U designation was associated with NASCAR blocks only and that isn't correct. A friend filled me in on uni-bore and I had to elaborate on that statement.

Also I believe a member did reply with the numbers on his 153 with all 4 cross bolted mains



Thanks Mike,

That was the info I was looking for. :cool:

Neal
 

Thumper

Active Member
Well we got around to uncrating another 197, and found this. Great info on dates??
Block stamped 0198U1269
Check out date on unibore paper
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Mike T

Well-Known Member
Visually the threaded holes around the freeze plugs is the only difference I can see vs a 153. A machinist friend of mine said there's a raised cam version. I know this was discussed earlier in the thread but he said the height difference is very subtle.
Good to see this stuff is still around 😎
 

Thumper

Active Member
Visually the threaded holes around the freeze plugs is the only difference I can see vs a 153. A machinist friend of mine said there's a raised cam version. I know this was discussed earlier in the thread but he said the height difference is very subtle.
Good to see this stuff is still around 😎
Mike, something else I asked about, never got an answer? Maybe you can clarify? Did 153s have a oil transfer groove in front and rear cam bearing locations in the block?
 

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Mike T

Well-Known Member
Mine are grooved front and rear.

Front is grooved from about the 1 to 7 o'clock position facing the block. Looking at the rear cam journal from the rear it's grooved from about the 11 to 5 position
 
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