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I think it could be done but the cylinder walls would be really thin. They are already thin to begin with thats why 400sbc heats up at idle easily. I think if you were to do it you would want a big crank but i truely have no clue if this is possible, but i was wonderign the same about my 400. I think it would have to be a limited use engine.
 

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59chevyapache said:
I think it could be done but the cylinder walls would be really thin. They are already thin to begin with thats why 400sbc heats up at idle easily. I think if you were to do it you would want a big crank but i truely have no clue if this is possible, but i was wonderign the same about my 400. I think it would have to be a limited use engine.
Untrue. 400's do not heat up at idle unless some doofus builds them incorrectly. Don't be affraid to build that motor up! I rode in a 427 about a month or two ago (1BAD80's car). He has it bored .060 I think, stroked out and runs 12:1 compression, a giant cam and pounds 700 horse out of the motor. Cruises down the street with a stock rado and a I believe a stock pump at 170 degrees or so.

You can't bore to 427, you have to stroke your motor out. Kits are available online, although due to core-shift in these blocks few stock castings are decent enough to build and bore to this degree.

K
 

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im having some over heating problems with mine but i think its due to a crappy fan. it only over heats when im in traffic or just sitting there. The fan i have on there flows less than 800 cfm(electric) so it doesnt get enough air through the radiator. when im driving it stays around 170-180 so that radiator works. I ordered a zirgo 3900cfm fan for it to hopefully fix my problem.
 

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Discussion Starter #5
thanks guys, i think thats what im gonna do for my 79 firebird, find a 400 that can handle the .060 over bore and stroke it for a 427 sb
 

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You'll have better luck selling an ice-cream sammich to an Eskimo.

If you do find a decent block, don't go and waste it with a huge overbore just for the sake of saying it's a 427. Do what's necessary to get the bores smooth and straight. Leave some room for another rebuild in the future. You'll thank yourself for it when the time comes for a rebuild.

Larry
 

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Discussion Starter #7
yeah, i found a 400 but they are getting rare, i shouldnt wreck it. maybe i should just buy a 427 aluminum block from world products i was lookin at this one aluminum block, 9.025/4.125 and 400M'' Billet cap or a 350M''Billet cap for only $3395.95...:)
 

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Huge over bores are a poor way of trying to up ci inches and hp, the thinner the cylinder wall becomes the bore flexing occurs which hinders ring sealing and output. This is to mention nothing of the reliability of the engine and as previously mentioned wrecking any chance of getting another rebuilt out of the block.
 

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Junkyard Kustoms
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Youll never afford it

Dude sorry to pop your bubble, but youll never have that much cash workin at moxies. If your quitting your job thats not helping . just find a farmer that will sell you a 427 out of a grain truck for less than that.... You also dont have that much knowledge in this type of thing as i recall i had to teach you alot that 6 month summer we had! Be carefull what you dream about because they can break you.Beside by the time your body work is dont youll have no money for a motor.
 

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Not possible on a 400 SBC, or SB Olds(very NOT possible on the olds). The walls are too thin, sometimes you can only go .020 over and no more. Just a fact. If you can manage to find a decent SBC 400 and bore it .060 over(have to check walls first), you can buy the 434 stroker kit and cal it a 440 :thumbup:
 

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87442lover said:
Not possible on a 400 SBC, or SB Olds(very NOT possible on the olds). The walls are too thin, sometimes you can only go .020 over and no more. Just a fact. If you can manage to find a decent SBC 400 and bore it .060 over(have to check walls first), you can buy the 434 stroker kit and cal it a 440 :thumbup:
tell that to 1bad, I've seen the motor first hand. Stock casting.

K
 

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oh yeah, I get it. Like I said before, I don't think its possible by bore only either. Heck, .060 over is only going to get you 411 or 412 cubes.

K
 

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that link that was posted says the kit comes with a Scat / Eagle 4340 3.875 crank, yet is says at the top 4.125 bore/ 4.000 stroke, something isn't makin sence. typo?
 

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The Smell of Nitro in the morn
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On a old cast 400 block, stock bore and a 4" stroke makes a 427.
The block MUST be prepped correctly, and a small base cam to make it work. I have about 5 K in my motor and done all the work.
Anyone who wants to dought it put up some cash $$$$ up , I need it to build my next motor with twin turbos.
I did not count the .030 bore cleanup for a 434 motor.
When going into a .060 bore its best to grout the block for strength and help with the lower thin casting, Still no heat problems.
The nice thing about a after-market blocks, its all machined for a stroker, I prefer a new rocket GM block.
Sonny Leonard built one that ran on 92 pump gas it was a 504 small block 1020hp around 875 ft.tq. with a GM aluminum block.
So whats in your wallet? How fast do you want to go.
This was talked about 2 months ago.
George :D
 

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Discussion Starter #19
hey, 1bad80, that link u posted for that 427 well thats the same block i want to buy for just over 3 grand, the link takes you to the crate motor they buit out of it but im just going to buy the block
 
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