Bore, Rod, Stroke?
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Bore, Rod, Stroke?
What are the benefits of increasing/ decreasing the size of these in an engine. If someone can fill me in or point me in the right direction.
Thanks Mike
Thanks Mike
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Car: yy wife, crazy.
Engine: 350, Vortecs, 650DP
Transmission: TH-350
Axle/Gears: 8.5", 3.42
Anytime you increase bore or stroke, you're increasing the displacement. That's always good for power, but not always good for MPG.
The easiest way to find the displacement of an engine is this formula.
Bore X bore X stroke X .7856 X number of cylinders = cid
Rod ratio is the length of the rod divided by the stroke. The higher the number the "better". I say "better" because what's better isn't always practical.
The easiest way to find the displacement of an engine is this formula.
Bore X bore X stroke X .7856 X number of cylinders = cid
Rod ratio is the length of the rod divided by the stroke. The higher the number the "better". I say "better" because what's better isn't always practical.
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Car: yy wife, crazy.
Engine: 350, Vortecs, 650DP
Transmission: TH-350
Axle/Gears: 8.5", 3.42
Oh...... go to www.Mortec.com and look at the Bore and Stroke list. That will help you figure out what engine has what combo.
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So what if I was to replace the 5.7 rods with 6.0 rods in a 350 what would the out come be. Does adding larger rods make a difference when selecting cranks or pistons?
Keep it coming guys
Keep it coming guys
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Originally posted by 89TurboV6
So what if I was to replace the 5.7 rods with 6.0 rods in a 350 what would the out come be. Does adding larger rods make a difference when selecting cranks or pistons?
Keep it coming guys
So what if I was to replace the 5.7 rods with 6.0 rods in a 350 what would the out come be. Does adding larger rods make a difference when selecting cranks or pistons?
Keep it coming guys
Is it worth tearing down an engine for? Probably not, but when building a new engine, I would say yes, it is worth the extra effort.
With the existing 350 crank, you would need to add pistons with the pin moved up to accept the longer rods, or you would stick the pistons right out the heads. You could use a shorter stroke crank, but then you decrese your engine size...
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Originally posted by 89TurboV6
So what if I was to replace the 5.7 rods with 6.0 rods in a 350 what would the out come be. Does adding larger rods make a difference when selecting cranks or pistons?
So what if I was to replace the 5.7 rods with 6.0 rods in a 350 what would the out come be. Does adding larger rods make a difference when selecting cranks or pistons?
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Car: 1966 El Camino Custom
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Re: Bore, Rod, Stroke?
Originally posted by 89TurboV6
What are the benefits of increasing/ decreasing the size of these in an engine. If someone can fill me in or point me in the right direction.
Thanks Mike
What are the benefits of increasing/ decreasing the size of these in an engine. If someone can fill me in or point me in the right direction.
Thanks Mike
http://www.chevyhiperformance.com/techarticles/71298/
You have to ask yourself what you want from the motor you want to build, then make a plan to get there. Be aware that there will be compromises. The trick is to limit them and still attain your goal.
From an engineering stand point, IMHO, the best place to begin is the fact that the standard factory SBC has a crank centerline to deck height of 9.025" and armed with that knowledge you can play around with combinations. Though the factory production crank strokes you would probably be interested in are 3.00", 3.125",
3.48", and 3.75", the aftermarket can accomodate anything.
Give us some goals and there is enough brilliant minds on this site to steer you in the right direction.
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Car: yy wife, crazy.
Engine: 350, Vortecs, 650DP
Transmission: TH-350
Axle/Gears: 8.5", 3.42
Originally posted by 89TurboV6
Thanks for all the info. Im going to play around with rod ratio stoke and bore #'s and see what I combos I can come up with.
Thanks for all the info. Im going to play around with rod ratio stoke and bore #'s and see what I combos I can come up with.
3.0", 3.1", 3.25", 3.48", 3.75"
There were 7 different bores, not including the overbores (.030", .040", .060") when rebuilding a SBC.
3.5", 3.671", 3.735", 3.75", 3.875", 4.00", 4.125"
And I don't even wanna guess how many different aftermarket strokes are out there.
We'll see you in a few weeks when you're done figuring them all.
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