I am getting ready to order my rotating assembly for my 383 and just need to know which rods I should go with. It will be a NA LT1 with forged crank, rods, pistons. My machine shop said 5.7, but I see so many using the 6 inch rods. Is one more suitable for blower setups and one for NA?

Just want to make sure I get the right ones.

Thanks

 

Usually you use a 5.7 inch rod on a blown 383 because it allows you to run lower compression and more boost. For a NA or nitrous motor, I'd stick some 6.0" rods in it myself.

 

ive always heard 5.7 rod stroker motors are easier to build. talk over pros and cons w/ your machine shop and go from there.

 

This has a had a lot of discussion, you might want to do a search. But without getting into the why's and wherefore's here's my take.

NA 383: 5.875 or 6" rod.
SC 383: 5.7" rod.

Rich Krause

 

I ran 5.7" rods on my turbo 383. Never really considered the 6" rods. The thinking w/ the 6" rod is that there will be less stress on the outer cylinder wall because of the longer stroke. The rod/stroke ratio is obviously better w/ the longer rod as well. However, you will have to clearance the bottom of the cylinders to clear the 6" rod. I've seen a motor that didn't do this...ouch.

 

thanks for the help.

I will go with the 6 inch rods. They were also reccomended by one of our favorite vendors; just wanted to get some more imput to make sure.

thanks

 

The 6" rod isn't as desirable for longevity reasons, due to the fact that you have more piston slap at the upper end of the cylinder because the wrist pin is closer to the ring lands thus making the piston shorter in height. However, with a 383 the stroke isn't huge so this shouldn't be a problem on a N/A motor. With a turboed are nitroused motor some prefer the 5.875 rod because the piston would be a bit more stable and wear less in the cylinder, PLUS with a shorter rod you won't hear the pistons when the engine is cold several thousand miles down the road because they would be more stable

 

I allways assumed the longer rod would be easier for wear, because of the straighter shot at the bore. The 5.7 will have less dwell at the top and bottom than the 6.0 so a SC application should use the 5.7 rods.

 

The longer the rod with a stroker application, the more the engine will wear near the top of the cylinder. THis is not to say it won't last a TON of miles, it will just cause the cylinder to go out of round sooner because there is less skirt on a shorter piston allowing it to bang around a bit more.