$O$OE

iTrader: (14)

which will u guys perfer to use 5.700" or 6.000'' and why? any difference?

ulakovic22

iTrader: (12)

There is no appreciable difference between the two choices. Choose based on budget.

$O$OE

iTrader: (14)

thanks

grn95t/a

iTrader: (10)

my engine builder as well as my tuner recommended the 6" for turning the engine to the 6600 i need to shift at.

James Montigny

iTrader: (13)

http://www.rustpuppy.org/rodstudy.htm

grn95t/a

iTrader: (10)

awsome info! man thats a hugh difference between the 6" and the 5.7"
i see why they both recomended the 6" now. thanks man!

James Montigny

iTrader: (13)

2% is 2% ...
It's really more effective with a stroker, or something built to handle more RPM.

Speed Density

iTrader: (38)

Wrong.

Lots of power adder guys run a shorter rod so they can have a larger piston crown.

There are differeneces, its not just a rod.

96capricemgr

iTrader: (1)

That is pure bench racing, nothing really informative about it.
If you want to be sucessful you will have to learn to seperate the real world from the theoretical.

Longer rod makes for a lighter piston, a lighter piston is easier on rod bolts and such. That is pretty much the end of the story.

grn95t/a

iTrader: (10)

and thats why i have my engine being built for me by a very respected and very well know ( in my area and others ) race engine builder. so it will be built once and do as i ask of it! no short cuts and no he said and she said to use this stuff. he basicly told me; if you want me to build it, were doing it this way so my reputation remains the way it is! i gladly sid yes sir! it will cost me twice as much and take 3 times longer to get it back in the car, but it will be time and money well spent!

96capricemgr

iTrader: (1)

Just to be clear I am not really taking sides on the 5.7-6.0 argument.

There is a lot to be said for doing it the way the machinists wants to do it. You force him out of his comfort zone and he will blame your decisions for any problems that arise.

1989GTA

I was looking at the price of Scat I-beam rods the other day and their was no price difference between the lengths. IMHO if building a new motor I would go with the longest rod that would fit and not have the oil pin get into the oil ring. Like was said above if nothing else you will wind up with a lighter rotating assembly.

ulakovic22

iTrader: (12)

Wow, some of you guys are really grasping at straws. This argument has been beat to death millions of times so just search and you will find tons of info. Unless you are building an all out 10.5 race motor or have to follow certain rules for a class there is no real difference in power output between the two rods.

Someone earlier posted about boosted applications and that's a valid point concerning ring placement, ring land thickness, etc., but if that's the case then the OP would be choosing a piston to suit his needs and the rod length wouldn't matter because if he did need an extra thick crowned piston then more than likely they will tell you what crank and rod combo it will work with.

Of course this is all speculation because the OP didn't specify what he is planning on doing or what application his motor is for. If you think the extra cost warrants the need for a 6" rod and want to use side loads, dwell time, etc for your arguement go right ahead, but you probably also think that a 4/7 swap on a BBC make a huge difference too.

1989GTA

With Scat Rods and Mahle pistons there are no extra costs.

NSTIGATR

iTrader: (4)

well at the current time im tryin to figure out the same thing. we are building a 383 in my lt1 with a p600b and a 50 shot of gas. i was told to run 5.7 rods because of the ring placement with a 6.0 rod being at the wrist pin and with increased cylinder pressure having the rings placed with a 5.7 rod is more suited for my application....

ulakovic22

iTrader: (12)

Just goes to show you it all depends on who you ask. Honestly it doesn't really matter. In your case assuming you don't already have aftermarket rods you will have to buy some so you can even explore a 5.85 rod if you wanted to.

NSTIGATR

iTrader: (4)

not tryin to hijack this thread.....

yea we dont have rods yet. something we can think about. guess ill talk to him tomm bout that idea....

looking online it looks pretty limited to run pistons for 5.85 rods. need comp ratio lower than ive been able to find pistons for, standard deck height, cometic head gasket and 56cc heads...

ulakovic22

iTrader: (12)

I was joking on the 5.85 rods, those are mostly used when building a 396 so a small CH piston is needed. Point is run whatever rod you want or are comfortable with because in the end it really doesn't matter that much.

fergymoto

iTrader: (129)

Lingenfelter ran 5.850 Oliver rods in their 383 LT1s. It's a happy medium that likely doesn't place the wrist pin in the oil ring lands. I haven't look at a piston for that rod length personally.

ulakovic22

iTrader: (12)

That's cool, I didn't know that. The only manufacture I know of that stocks that piston is SRP, but I'm sure others have them as well, just have to call and ask.