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Discussion Starter #1
Just for the record, you can bore up to .060 on most engines and the most you can stroke a 3.8 to is 4.6 on a non s/c block and 4.4 on an s/c block
Rick
 

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ok :wtf: kinda random though
 

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Discussion Starter #5
cid for 3.8

yes someone asked this in another post thought I'd pass along something useful :D
 

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but faulty ;)

I'm doing mucho measuring and I know I can get more
in both cases. However, these figures do work in nearly every case.
SAFELY!
 

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Charles' engine will be bigger in at least one of these areas.
 

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.060 overbore??? Maybe, but that sounds like a lot to me....can you even buy pistons for that much overbore, seems to me the cylinder walls would be getting sorta thin too. .030 to .040 is what you usually hear about. The main reason for boring is to clean up messed up cylinder walls and to straighten up a cylinder that has gotten mis shapen from wear, there is generally no reason to go more than necessary to achieve these objectives, you aren't really going to get enough increase in your displacement to make an appreciable difference in my opinion. For that stroking is the definite way to go. Another thing that used to be done more in the days of bigger block engines, but not so much now I would think is de-stroking, or shortening the stroke, this made a smaller displacement but supposedly allowed the engine to wind up faster, Corey, being a Chevy man you might know more on this than I would???
 

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Discussion Starter #12
With all due respect RGR, .060 overbore is standard( ok standard for most) practice, and anything over that is risky. I will stay within accepted practice and still kill rice handily.
 

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Well the 68 Camaro Z28 had a 302CID motor in it that was derived from a 327 block with a 283 crank it was a long winded car that did not get going till 4000 rpm but it was really designed as a race car for road course. But I must say when you talk Big block Chevy you have the big ass Rat motors that were 454 punched out to 513 and bigger going 60 over. I use to take the 350's to 30 over and that was enough for me but others went further
 

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plstktnkr2 said:
With all due respect RGR, .060 overbore is standard( ok standard for most) practice, and anything over that is risky. I will stay within accepted practice and still kill rice handily.
U are right on plstktnkr2, I agree that 60 over is recognized as
safe and sane for any V6 I have seen. But for the meticulous
machinist U can measure and maybe get more!
 

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Discussion Starter #16
www.moranaracing.com has viable stroker kit for 4.6
 

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They list it (4.6 stroker) but I've heard it was a bust.

Not from Morana, but from a customer who lives there.
Said it still needed balance work. I'm sure a 4.6 can be done,
my machinist's first level stroker (offset ground 4.2 crank)
comes out at 4.5 liters with only a .030" overbore. We're
not fooling around with factory parts and hyper pistons,
these will be serious power-adder capable strokers :D
Later I'd like to do an econo-stroker w/hypereutectics
but most ppl. now want the forged bottom ends.
 

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Rick0636 said:
can you even buy pistons for that much overbore, ...
The main reason for boring is to clean up messed up cylinder walls and to straighten up a cylinder that has gotten mis shapen from wear, there is generally no reason to go more than necessary to achieve these objectives...
ummm, c'mon Rick... that's what custom pistons are for. You can have
them made in any size you want. :p
And yes that's the normal reason for boring... to clean it up and straighten
it. No you won't get much power from a couple extra cubes but the
advantage from being able to unshroud the valves that much more is
why one might want to bore further.
Yes 60 is the rule of thumb for safe. If you take careful measurements on
your specific block to make sure you don't have problems with core shift
then you can go further.
 
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