Thread: how much more horse power do you get when you bore a engine.060

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well the heads do work better with a bigger bore and like i said if the block is good and can take a over bore i think .100 is where you can see it so get out your the block rock

[QUOTE=DennyW]

"The old rule is still accurate. The only thing better than lots of cubic inches is more cubic inches".

Denny is right on the money. All things being equal, 351 ci will outpull 350 ci. We're not talking Chevy's vs. Ford's here, rather the same block. With everything else being exactly the same, bigger is better. You're not going to feel it seat of the pants, but a dyno will show it. If this wasn't true, people wouldn't be wasting money building 383's and small blocks over 400 for racing amd no one would touch big blocks. The line we use to use was "There's no substitute for cubic inches."

Oldman2

I may be old, but I'll be older tomorrow

I think the problem with this whole discussion was just the way that the original question was asked. I think it's obvious to all of us that an increase in cubic inches will yield an increase in power. But as mentioned, it wont be anything that will be felt in your 'ass' dyno. After your boring is done, you will do new rings, gaskets, maybe other machine work...other new parts maybe. That's the stuff that will build your power up. I am also one who will take a virgin block and bore it to whatever I decide based on what Im building. I dont worry about having anything left to do it again. If I want to build a specific engine, as I did on my last build, then it requires a certain bore, and certain stroke. If the bore is stock, and I have to go .100 over, then so be it. And increasing the bore diam. will INCREASE c/r, not decrease it...but I think this has already been verified.

2 ways to go fast. Cubic inches or cubic dollars.

But having both makes you fastest........

yes i did build a 100 over big block it took 4 to find one that could go to it that was over20 years ago and it is still out there i have a new donovan bored to the max if the walls can take it do it. i have sleeved the the big bore stuff 4.600 when things go bad to. so it is not the end of the world if you have to sleeve one or two holes

.....Do yourself a BIG favor & don't over bore your engine any more than necessary! I had my 400 small block bored .060 over to 413 when it didn't need to be overbored at all. I figured "hey if I can get 13 more cubes it'll be 13 more HP".... Well, now my engine needs to be bored & it's maxed out. So I'm having to re-sleave a cylender. Luckily for my it's only one cylender.... It could have been all 8 in which case I'm just scrap the block..... Live & learn huh???? take care, Bill

bigger isnt always better

This discussion needs to focus on the original question which seemed to be about the HP resulting from just an overbore with no other changes. I cannot see how the compression could go down when the swept volume is increased and the combustion chamber remains the same. Since the swept volume increases (slightly) and the compression increases (slightly) the HP should increase (slightly). However this assumes keeping the same type of new pistons, same cam, same ignition, same induction etc. Regarding unnecessary boring, just think how many flathead blocks might be still running but for some overbore which rendered the blocks unuseable after heat cracks? (On the other hand that siamesed double exhaust port in the middle of the block is a design flaw; one that was corrected in the ARDUN heads but don't get me started on that! http://www.oogabooga.ca/oogaboogapag40.htm )

Don Shillady
Retired Scientist/teen rodder

Ok, lets see, if I take my 283 ci chevy and bore it .120 to a 302 ci which motor has more power? the 283 or the 302? if you answered 302 then you must get some horsepower out of a bore. Like it was mentioned, will not be enough to feel and should not be done for the heck of it unless you were going ALL OUT!

New here and this thread inspired and compelled me to register.

It is as someone said, the question is flawed. The correct answer can only be yes. The wording of the question, as well as the subject and dimensions given subconsciously demand that the average American wrench bender try to explain why or why not. The fact is and must be, all other factors being equal, (the magic phrase the original poster should have used) increasing displacement must increase power for performance of work. No matter how small, any increase is a yes answer. This is just a fact of nature.

Just call me mooseye!

Wow - took you eight years to come up with that, eh? Thread's previous post was July 13, 2006. jus sayin..

Must be one of them there procrastinator fellers....

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Hey, blame it on google and lack of attention to dates. I don't even remember what I was searching for when the thread came up.
And it would have been difficult for me to come up with that any sooner since I just got in today.
Have a good one fellas, no troll here but I have been know to procrastinate about putting something off till tomorrow.

Okay, now I remember. I was searching for almost the exact phrase as the title of this thread. The difference is that I wanted to know exactly/as close as possible with the present technology, how much of an increase for a .010 overbore out of a 200cc jug. I first thought maybe there was a chart somewhere that would give some ball park figures. After thinking about it, i'm sure there are way to many variables for such a chart to be viable if it existed. Maybe a general formula? I slept through Algeria.

Originally Posted by mooseye

.... After thinking about it, i'm sure there are way to many variables for such a chart to be viable if it existed. Maybe a general formula? I slept through Algeria.

Slept through Algeria? The whole country?

Sorry, Moose, that self setup was simply too good to pass up.