OUTLAW EAGLE MANUFACTURING

[big block]

so planning on having a 383 short block built for my eagle 19 sport, undecided on 5.7 or 6.0 rods. i plan on using all the parts from my zz4 350 and picking up the zz383 camshaft.

ok engine guys whats your preference on rods 5.7 or 6.0?

[TOP DAWG]

the longer the conecting rod, the longer dwell time you have. Dwell is the amount of time the piston remains @ TDC, the longer the dwell the better detonation resistance your engine will have.

[riverboater]

longer rod, more dwell, higher static compression, more torque. check the difference between the 350 olds and chev, chev has 5.7 and the olds 6.0 rods. check the torque numbers.

[boosted]

top dawg I think you got it backwards. Deto resistance has a time component to it. A short rod is better for less deto because it is at tdc for a short period of time thus not allowing the heat of compression enough time to create deto. A longer rod is better for rod angle and easeier on cylinders, pistons allowing a little better rpm with less side loading vs the same stroke and a short rod.

Unless you a building an all out race engine you really won't notice any difference.

[Hines]

Het Big Block Your engine guy should know what you need, this deto thing its just set up timing,jets,feul,etc. learning curve.LOL.Later.

[Rapid Transit]

the length of the rod determins where the pin mounts through the piston head, and will then determin the comp ratio, the piston should not be at tdc any longer with either one, once you hit tdc you are immediatly going past, the piston is either going up or down,.... so your pison heads have to match your rods so that they mount properly

[TOP DAWG]

Longer rods provide for a longer dwell at piston TDC, this is a known fact ! keeping the combustion chamber small for a longer period as the expanding gases push against the piston. This extracts more power from a given air/fuel mixture thus increasing combustion efficiency. And so much like with good quench, you've once again raised the amount of compression that you can utilize for a given combination (and octane) before detonation becomes a concern. Also, much as does a stroker set-up, longer rods benefit the power band (read "torque curve") with the largest advantages in the low and mid-range RPMs. Even in a stock bore and stroke combination, longer rods can give you some of the effect of a stroked engine. And in fact on a shorter stroke, an even longer rod can be used within the given limits of practicality, this meaning pin location on the piston. While on a pure race engine, particularly such as in a drag race application where run durations are minimal, pin location can be pushed to the limits. But for a long living boat engine there are other obvious considerations. Still, with a 350 Chevy (3.48" stroke), a 6.125" rod (5.7" is stock) can be used with no problems, with the correct piston of course. For a 383 (3.75" stroke), you'd probably want to limit it to 6" for normal use.

A good example is the 340 Mopar, it still manages to have a broad and strong torque curve, even with a very short stroke of 3.31" . It uses rods that are just under 6 1/8". I can't help but wonder if it was simply a cost-saving matter for Chrysler to keep the stroke the same for the 340 as it was in the 273 (and 318) or were they ahead of their time in experimenting with rod length combinations? Perhaps it was some of both

One other important benefit of longer rods is that they also reduce side-loading against the cylinder walls. This in turn reduces friction, heat and so of course, wear.

[boosted]

Well Top Dawg we may have to agree to dissagree to an extent. Having the piston stay at tdc longer will give the compreseed gasses more time to self ignite. However this would be the case before the piston reaches tdc. After tdc you may be correct with gaining some torque but it will not aid in cooling combustion temps or pressures so your chance of deto is not reduced. Jon Kaase likes to run a short rod for emc as he says the piston action is very quick thus helping keep detonation at bay.

I do totally agree though that it is always an advantage to run a longer rod. It will usually allow you to run less ign lead for the peak power wich is always more effeciaent and better for the engine.

[TOP DAWG]

Agreed ! there are one million ways to skin a cat , with advantages and dissadvantages to all.

[big block]

well where im at is looking at the longevity of the engine im building, i have not done a sbc 383 before, have done a few sbc 350 and bbc 454 and on those engines the wrist pin does not enter the ring groove area, the wrist pin enters the ring groove on the 6.0 rods from what i have read does it also on the 5.7 rods? also the 6.0 rod having a shorter pistion has less stability in the cylinder bore. as you said there dawg are these high reving boats normal use? so im aming for 450 to 500 hp from the sounds of it im within limits of theses pistion and rod combinations.

[Arthur]

Need a crank?

[big block]

[Arthur]

A perfectly good crank that came from a AMS 383. Been sitting in the shed since I bought my ZZ383. Was checked out by the boys at AMS when my top end let go and was deemed good! Has around 65hrs on it. Got that, a cam, oil pan and a few other goodies as well. All with the same hrs.

[big block]

[Arthur]

No sir