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Old Jan 6, 2018 | 03:28 PM
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Were the C3s all 2 bolt mains? And if you have a 383S do ya think that they added 2 more bolts to each one?
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Old Jan 6, 2018 | 03:38 PM
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Not all C3's had 2 bolt mains. You can find 2 or 4 bolt main blocks in just about any of the Chevy car/trucks of that era that had a SB installed. Even some blocks with the same casting numbers had either 2 or 4 bolt.
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Old Jan 6, 2018 | 03:47 PM
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Originally Posted by jhopper408
Were the C3s all 2 bolt mains? And if you have a 383S do ya think that they added 2 more bolts to each one?
L48's were supposed to be 2 bolt (ZQ3s from 69-70 are 4 bolt) but there are many instances where people have found 4 bolts used in a L48 engine.

Are you asking if it is common practice to add 4 bolt caps when stroking a 350 to a 383? Usually it is recommended but there is no way to tell if the previous owner did or not without dropping the pan.
Last edited by Dynra Rockets; Jan 6, 2018 at 03:47 PM.
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Old Jan 6, 2018 | 03:58 PM
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Yeah that's what I figured. I don't have the spec's from the guy I bought it from. Bummer. But I would think that common sense would tell ya that it would be stronger.
plus with 450hp. I think that my C5 had 6 bolt mains.
Thanks
John.
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Old Jan 6, 2018 | 03:59 PM
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Originally Posted by jhopper408
yeah that's what i figured. I don't have the spec's from the guy i bought it from. Bummer. But i would think that common sense would tell ya that it would be stronger.
Plus with 450hp. I think that my c5 had 6 bolt mains.
Thanks
john.
a z06..
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Old Jan 6, 2018 | 05:59 PM
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C5 with an LS motor-- completely different animal.

Look at the casting number on your block, and see if there are any numbers on the stamp pad. That could tell you what is there.
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Old Jan 6, 2018 | 06:04 PM
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Would it be in the Vin# . Or just a different stamping?
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Old Jan 6, 2018 | 09:04 PM
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A two bolt L-48 with ARP main bolts is good for 500 HP.
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Old Jan 6, 2018 | 09:24 PM
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That's good to know!
thanks
John
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Old Jan 7, 2018 | 08:08 AM
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Originally Posted by REELAV8R
A two bolt L-48 with ARP main bolts is good for 500 HP.
I've been told the same thing too John. "Many other things are likely to go south before the 2-Bolt Main Bearing Caps do."

Steve
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Old Jan 7, 2018 | 12:16 PM
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Wow Steve. Thanks. I just figured that with all the torque One of them would let go.

John
Last edited by jhopper408; Jan 7, 2018 at 12:17 PM.
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Old Jan 7, 2018 | 01:00 PM
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Originally Posted by jhopper408
Wow Steve. Thanks. I just figured that with all the torque One of them would let go.

John
later '73+ 400's had two bolt, and it was factory rated at 400 ft lbs. Its not just torque, its more a function of torque and max rpm if 4 bolts are needed.
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Old Jan 7, 2018 | 01:11 PM
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Originally Posted by Dynra Rockets
later '73+ 400's had two bolt, and it was factory rated at 400 ft lbs. Its not just torque, its more a function of torque and max rpm if 4 bolts are needed.
Does having a 3500 stall make any difference?
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Old Jan 7, 2018 | 01:52 PM
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the ole 4 vs 2 opinions.
GM did have 2 bolts that had some power.
like said, rpm is a big factor.
I would say, steel crank helps with 2 bolt.
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