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02-09-2013, 07:23 PM | #1 |
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389 Pontiac?
How far can you safely bore a 389 block? Also turn down the crank?
1965 vintage...and for the street. (Asking for a friend.) |
02-09-2013, 10:58 PM | #2 |
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Re: 389 Pontiac?
Ive gone to std. 400 bore before. Then again, I just got done boring one to .040 and ran into water in one of the cylinders. Best to have your machinist sonic test it. That way there's no suprises.
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Phil Hudlow 6678 (S/C, S/G, ET-PRO) |
02-09-2013, 11:20 PM | #3 |
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Re: 389 Pontiac?
Back in the mid 70s, I was boring a Chev 350 block .020" for a SS build after a few hours of deburing and one cylinder opened up into a large air pocket. The block was scrapped.
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02-09-2013, 11:24 PM | #4 |
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Re: 389 Pontiac?
Yup! Ive had that happen to me before, too
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Phil Hudlow 6678 (S/C, S/G, ET-PRO) |
02-10-2013, 08:51 AM | #5 |
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Re: 389 Pontiac?
I have a couple of similar stories and it has always left me scratching my head. How did an engine survive 80k miles being driven every day for years with a cylinder wall that was less than .050" thick?
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02-10-2013, 11:53 AM | #6 | |
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Re: 389 Pontiac?
Quote:
Different day, different mold at the foundry I guess. That or the factory had a huge supply of +.022" pistons they needed to unload!
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Jeff Lee 7494 D/S '70 AMX |
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