SBC 400 Bored .040? - Chevelle Tech
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post #1 of 12 (permalink) Old May 5th, 12, 1:30 AM Thread Starter
Alexander
 
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SBC 400 Bored .040?

Hey guys, what would you guys think a SBC 400 bored .040 actually is?

I have absolutely no idea on how what to call it, mainly because I'm still new to the innerworkings of cars. Thanks in advance!

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SBC 400 bored .040 with Aluminum Heads, 3.73 Posi, +202/160 Valves, Roller Rockers, Patriot Headers, Edelbrock RPM Air Gap Intake, Flowmaster Exhaust, Holley 80508S Carb, Aluminum Radiator, Quick Ratio Steering Box, and a new Alternator.
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post #2 of 12 (permalink) Old May 5th, 12, 2:21 AM
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Vince
 
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Re: SBC 400 Bored .040?

call it a 408...
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post #3 of 12 (permalink) Old May 5th, 12, 2:22 AM
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TerribleTom II
 
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Re: SBC 400 Bored .040?

still call it a 400 or 406. it's actually close to 408 cu. in.

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post #4 of 12 (permalink) Old May 5th, 12, 5:04 AM
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Derrick
 
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Re: SBC 400 Bored .040?

call it a 305..

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post #5 of 12 (permalink) Old May 5th, 12, 8:10 AM
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Dave
 
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Re: SBC 400 Bored .040?

Quote:
Originally Posted by Tom Mobley View Post
still call it a 400 or 406. it's actually close to 408 cu. in.
If I'm talking to a car person, who knows about engines, I'll call mine a 406 - because we all know what a 406 is: a .030 over 400.

If I'm talking to someone who may not know what a "406" is, when they ask what engine I've got under the hood, I usually say "a small block 400", just to keep it simple.

_____________________________________
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post #6 of 12 (permalink) Old May 5th, 12, 9:28 AM
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Darren
 
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Re: SBC 400 Bored .040?

Kinda of off topic but, on avarage what is the max you can bore a 400 sbc before the walls get too thin? I know to sonic test it but I'm just wondering what is the "norm". This would be for a fairly mild street car.

Sorry for the hijack.

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post #7 of 12 (permalink) Old May 5th, 12, 9:54 AM
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Re: SBC 400 Bored .040?

i would call it a 409, always fun to add to the confusion, lol

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post #8 of 12 (permalink) Old May 5th, 12, 10:31 AM
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Bill
 
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Re: SBC 400 Bored .040?

Call it a 400 bored .040 over

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post #9 of 12 (permalink) Old May 5th, 12, 11:18 AM
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Dave
 
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Re: SBC 400 Bored .040?

Quote:
Originally Posted by 71454Chevelle View Post
Kinda of off topic but, on avarage what is the max you can bore a 400 sbc before the walls get too thin? I know to sonic test it but I'm just wondering what is the "norm". This would be for a fairly mild street car.

Sorry for the hijack.
I don't worry about .030 over, but if it needs more, I get it sonic checked first.
Perhaps a machinist or two will chime in and say how far they typically can be safely bored... also, out of curiosity, I'd like to know what the magic number is when they sonic check the cylinder walls - what is the minimum thickness recommended?

_____________________________________
68 Chevelle
flat top 406, AFR 195's, XR286R, RPM AirGap
750 Holley DP,TH400 w/brake, 4000 stall FTI
3.31 gear, 12 bolt
... for now.
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post #10 of 12 (permalink) Old May 5th, 12, 12:57 PM
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Re: SBC 400 Bored .040?

Some are junk at only .030" over, while others are fine at .060".
Years ago David Vizard pulled a couple from junkyards and found they would safely go to 4.200", but...

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post #11 of 12 (permalink) Old May 5th, 12, 1:45 PM
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Re: SBC 400 Bored .040?

I'd think it is 6th Grade Math....

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post #12 of 12 (permalink) Old May 5th, 12, 2:59 PM
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Re: SBC 400 Bored .040?

Quote:
Originally Posted by novaderrik View Post
call it a 305..
I'm putting my 307 markers back on but it has a 406 under the hood.
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