Reasons to use a 6.0 rod in a 350
07-12-2009, 02:51 AM
#2
Le Mans Master
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http://www.iskycams.com/techtips.php#2005
For street strip use , better things to spend your $$$ on.
For street strip use , better things to spend your $$$ on.
07-12-2009, 07:30 AM
#4
Intermediate
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i run a 5.7" 350 rod in my 400 personally. mainly since i feel it is a stronger/better rod plus the piston compression height is shorter and thus lighter. otherwise i wont spend any $ on a longer rod for anything...
07-12-2009, 09:02 AM
#5
07-12-2009, 09:22 AM
#6
6 inch rod reduces piston side load friction.reduces cyl wear.improves VE by delaying peak piston speed till later in the stroke,when the intake valve is opened further.
07-12-2009, 09:56 AM
#7
Team Owner
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St. Jude Donor '05
For most street builds 5.7 is fine but if youre going to twist it get the longest rod you can in there. Like them on strokers to in an effort to reduce sideloading and egg shaping the cyl.
Stock 400 rod is 5.56 (or 5.65?)
Stock 400 rod is 5.56 (or 5.65?)
Last edited by cv67; 07-12-2009 at 10:46 AM.
07-12-2009, 10:27 AM
#8
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msd is set at 6400 on mine. seems pretty happy there too, even with a hyd flat tappet camp, comp XE284. usually shift at about 6200. need to get the th350 finished and get the first 11 under my belt...12.09 is just too close to let it stay 
07-12-2009, 11:53 AM
#9
07-12-2009, 01:13 PM
#10
Melting Slicks
I started to write a reply to this yesterday as I worked a lot with it and did not like the way it read sounded.. Short story from my experience is it depends on RPM range intended use IE torquey street engine VS top end killer and cylinder head flow availability. Low end torque = shorter ratios 1.55 to 1.65 small heads and high rpm or max output race = 1.7 to 2.5.... It is all about peak airspeed in the port and mechanical advatage at the crankpin. A daily driver Vette for me would be 1.55 to 1.65 a race SBC 1.7 to 2.0 max a F1 engine and yes have tuned them too 2.4 to 2.8.. at 20k rpm..LOL... This is the mild version so ....
07-12-2009, 08:10 PM
#11
Race Director
With proper parts choice longer rods can result in a reduced recipricating mass. (My 12.1:1 355 thrives on pump gas. The 6" rods from Scat weighed less than the stockers, the Mahle Power Pack pistons were lighter than the stockers too, and the machinist had to remove weight from crank IOT balance the rotating assembly "win, win, and win)
Last edited by aboatguy; 07-12-2009 at 08:19 PM.
07-13-2009, 05:36 AM
#12
Safety Car
why not run a ZZ-383 cola crank and clearance the stock block a bit and then you can run production length rods and still get 383 cubes out of it?
My friend is building a 396 kind of like this but I believe using 6.00 carillo rods and this same crank & .030 over.
My friend is building a 396 kind of like this but I believe using 6.00 carillo rods and this same crank & .030 over.
07-13-2009, 07:34 AM
#13
Drifting
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I started to write a reply to this yesterday as I worked a lot with it and did not like the way it read sounded.. Short story from my experience is it depends on RPM range intended use IE torquey street engine VS top end killer and cylinder head flow availability. Low end torque = shorter ratios 1.55 to 1.65 small heads and high rpm or max output race = 1.7 to 2.5.... It is all about peak airspeed in the port and mechanical advatage at the crankpin. A daily driver Vette for me would be 1.55 to 1.65 a race SBC 1.7 to 2.0 max a F1 engine and yes have tuned them too 2.4 to 2.8.. at 20k rpm..LOL... This is the mild version so ....
Road track motors benefit more that drag or street.
TJM
07-13-2009, 06:31 PM
#15
Drifting
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The biggest advantages of the longer rods is a longer dwell time at the top of he compression stroke, probably something like a 5 degree
improvement with the 6" rod over stock 5.7". This allows more pressure and that makes power.
The longer lever makes more torque.
So you get more "twist" and better combustion for "x" amount of fuel.
Pistons do become an issue, but one goes with the other
TJM
07-13-2009, 07:04 PM
#16
07-13-2009, 07:16 PM
#17
Safety Car
the zz-383 uses 350 bore.
seeems to me stroke affects cubic inches ... right?
07-13-2009, 08:03 PM
#18
07-13-2009, 09:08 PM
#19
Le Mans Master
To be a little more clear a stock 350 is 4.000 x 3.48
A 377 Can either be a stock 350 block with a 3.75 stoke crank 4.000 x 3.75, or it can be a 400 block bored .030 over with a 3.48 stroke crank 4.155 x 3.48
A 383 Can be either a 350 block bored .030 over with a 3.75 stroke crank 4.030 x 3.75, or it can be a 400 block bored .060 over with a 3.48 stroke crank 4.185 x 3.48
A 385 is a 350 block bored .040 over with a 3.75 stroke crank 4.040 x 3.75
A 388 is a 350 block bored .060 over with a 3.75 stroke crank 4.060 x 3.75
A 396 (395) is a 350 bored .030 over with a 3.87 stroke crank and usually a 5.9 rod.
So if its a 350 block, and its in fact a 383 then the bore is 4.030.
A 377 Can either be a stock 350 block with a 3.75 stoke crank 4.000 x 3.75, or it can be a 400 block bored .030 over with a 3.48 stroke crank 4.155 x 3.48
A 383 Can be either a 350 block bored .030 over with a 3.75 stroke crank 4.030 x 3.75, or it can be a 400 block bored .060 over with a 3.48 stroke crank 4.185 x 3.48
A 385 is a 350 block bored .040 over with a 3.75 stroke crank 4.040 x 3.75
A 388 is a 350 block bored .060 over with a 3.75 stroke crank 4.060 x 3.75
A 396 (395) is a 350 bored .030 over with a 3.87 stroke crank and usually a 5.9 rod.
So if its a 350 block, and its in fact a 383 then the bore is 4.030.