BB bore 30 or 60 over
Thread Starter
Burning Brakes
Joined: Mar 2004
Posts: 923
Likes: 4
From: Austin Tx
BB bore 30 or 60 over
my 454 doesn't need to be bored, but I guess since it is going to machine shop for cleanup and honing, should I go 30 or 60 over and I think 30 over is 468 cu in but what will 60 over make it? Is it worth the extra power and what will it cost ballpark to bore 60 over
thanks, Greg
thanks, Greg
Race Director
Joined: Nov 2000
Posts: 11,872
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From: Waterloo ontario Canada
A 454 bored .030 over is a 460 and .060 over is 468. I would only go .030 for cleanup , that leaves another cleanup on the bore.
In some cases a 454 can go .120 over but that is risky
In some cases a 454 can go .120 over but that is risky
Team Owner
Joined: Apr 1999
Posts: 21,953
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified
4.250 X 4.00 = 454 ci 4.310 X 4.00 = 466.9 ci commonly called a 468.
Additional ci gained by boring is really a very small % and the performance is minimal with everything else being the same. Cleaning up out of round is normaly the reason for over bore.
Additional ci gained by boring is really a very small % and the performance is minimal with everything else being the same. Cleaning up out of round is normaly the reason for over bore.
Thread Starter
Burning Brakes
Joined: Mar 2004
Posts: 923
Likes: 4
From: Austin Tx
thanks guys, I have only bought crate motors in the past so this building engines from scratch is new to me. The engine came with flat tops but with the 049 heads I think the comp will be too low so I'm thinking of a dome piston to get the comp up around 9.5:1, that way if I get better alum heads in the future with smaller chambers I still have room to go up to 10:1
Pro
Joined: Sep 2002
Posts: 653
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From: Dickinson (Houston) Texas
I have the same decision for my 454. I thought about .060 over, but the block really does not need that. If the block is bored .030, that would leave more material in the cylinder which will allow the engine to run a little cooler.
Norval makes a good point in that going .030 over leaves room for another bore thereby stretching the life of this particular block.
www.bigdogvettes.com
Norval makes a good point in that going .030 over leaves room for another bore thereby stretching the life of this particular block.
www.bigdogvettes.com
Le Mans Master
Joined: Aug 2003
Posts: 7,720
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From: Chattanooga TN
The more you bore a block, the harder it is too keep cool. There is less metal to dissipate the heat with. I would go the minimum required to clean it up. It it will clean up standard, leave it standard.
