153 casting

[434nova]

Is all 153 blocks 4.1 stage 2 engines ? Just making sure that 153 blocks didn't come 3.8 cause I heard of issues with the 3.8 stage 2 blocks. Thanks for the help.

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[we4Mateo]

I think a 3.8L is a Stage I block if it is a stage engine. I believe all 153 blocks are Stage II.

 

[forcefed3.8's]

All 153's were on center 4.1's. There are 3 different versions, 4 bolt center with 2 bolt outer, 4bolt center with 4 bolt outer, 6 bolt center with 4 bolt outer, in order of early to late. There are also raised cam versions.
There are stage 1 and 2 3.8 and 4.1's off center.
The 3.8's were casting 012. The stage 1's had 2 bolt mains and 8 head bolts, while the stage 2's have 4 bolt center with 2bolt outers and 14 head bolts. The stage 1's can be machined into stage 2 4 bolt mains and 14 bolt heads.
The 4.1's were casting 016. The stage 1 vs stage 2 is the same as the 3.8's
Stage 1 and Stage 2 had the same casting numbers, but different part numbers in the GM parts catalog.
The on centers were the latest versions, the off centers were the first.

 

[we4Mateo]

All 153's were on center 4.1's. There are 3 different versions, 4 bolt center with 2 bolt outer, 4bolt center with 4 bolt outer, 6 bolt center with 4 bolt outer, in order of early to late. There are also raised cam versions.
There are stage 1 and 2 3.8 and 4.1's off center.
The 3.8's were casting 012. The stage 1's had 2 bolt mains and 8 head bolts, while the stage 2's have 4 bolt center with 2bolt outers and 14 head bolts. The stage 1's can be machined into stage 2 4 bolt mains and 14 bolt heads.
The 4.1's were casting 016. The stage 1 vs stage 2 is the same as the 3.8's
Stage 1 and Stage 2 had the same casting numbers, but different part numbers in the GM parts catalog.
The on centers were the latest versions, the off centers were the first.

Thank you! Great info I've always been interested in knowing.

 

[we4Mateo]

I was born too late to get this stuff when it was still available. I'd love an off center stage block, but finding a virgin one now has to be about impossible. Like old 427 Cobras, their use was not conducive to preservation unfortunately for me. T/A block I guess.

 

[forcefed3.8's]

I was born too late to get this stuff when it was still available. I'd love an off center stage block, but finding a virgin one now has to be about impossible. Like old 427 Cobras, their use was not conducive to preservation unfortunately for me. T/A block I guess.

Yep, when I was 17, I had a chance to buy a bunch of stage 2 stuff, but only had enough money to put gas in my car and food in my belly. The price when new was way cheap compared to what it goes for now.

 

[rag231]

When I first got my hard top GN I was offered a full stage 2 for $3000. The usual Busch motor that needed conversion. The final price of the motor running in my car scared me away. It would have been close to $25K+ back in 1997. My first motor was an 4.1 offcenter with M&A heads on it. They had been welded up so many times. They were shaved to death. The guy who I brought the car from from was a Mustang guy and he bumped the compression up by shaving the crap out of the heads until he bent vavles and tore up pistons. He sold me the car not running and I took the motor out and put in a stocker. I still have that off center shortblock. I will rebuild it soon after I get my on center up and running. The good old days when I could find tons of stage 2 motors for $2500 to 3000.

 

[434nova]

Cool so all 153 are 4.1 thanks

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[750H.P.V6]

There were two bore sizes available for 153 blocks. One was approx. 3.790" and the other was 3.960". GM once sold the smaller bore block under a different P/N and considered it a 3.8. Both blocks are identical with the exception of the bore size.

Neal

 

[norbs]

You can;t machine a stage I block to 4 bolt mains if it was drilled at the factory for stock internal oiling....

 

[434nova]

Can the 153 blocks with the 3.790 blocks go to 4.000 bore safely ? The reason I ask is cause the 153 block I was looking at has the 3.8 bore and the block doesn't have 4.1 stamped on it. Thanks

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[750H.P.V6]

Can the 153 blocks with the 3.790 blocks go to 4.000 bore safely ? The reason I ask is cause the 153 block I was looking at has the 3.8 bore and the block doesn't have 4.1 stamped on it. Thanks

Posted from the TurboBuick.Com mobile app

Yes. Only the earliest On center blocks had the 4.1 liter designation cast into the block. It's the same block with a smaller bore size.

Neal