blackbird345

Anyone know? I'm using them with Diamond pistons.

BIG_MIKE2005

iTrader: (116)

no but your piston & head CC selection will.

BlackScreaminMachine

iTrader: (17)

yup, often, comparitivly the longer rod = smaller piston and the piston will dwell at TDC longer comparitivly to a shorter rod....

BIG_MIKE2005

iTrader: (116)

6.125 is stock rod length. So like I said, it'll come down to pistons & combustion chamber size.

Beaflag VonRathburg

iTrader: (176)

Stock rod length is 6.098.

BIG_MIKE2005

iTrader: (116)

So why do all the vendors sell 6.125 as replacement length rods??

BlackScreaminMachine

iTrader: (17)

Often replacement pistons have updates and these rods are supposed compensate for the chng. My LT1 rebuild book spoke directly about this.

Scoggin Dickey

iTrader: (34)

6.098" is indeed stock length. 6.125" is the most common after-market rod length for these engines. The stroke, rod length, and compression height of the piston all have to be designed together to make sure the pistons aren't .050" out of the hole

To make this into a short lesson: (half the stroke) + (rod length) + compression height - deck height = how far pistons are in or out of the hole.

So a 4" crank, 6.125" rod, and 1.120 CH piston = pistons out of the hole .005" on a standard 9.24" deck height block.

BIG_MIKE2005

iTrader: (116)

So are you sayin the only true stock replacement rod is a GM stock rod?? All others require aftermarket pistons??

Scoggin Dickey

iTrader: (34)

Not really...several manufacturers make a 6.100" rod also that work with stock pistons and crank....that just pushes the stock piston another .002" out of the hole, which is fine in most cases.

blackbird345

I'm using these rods with -16cc dished pistons, I was told it was suppose to lower the CR to 9:1

BIG_MIKE2005

iTrader: (116)

was that calculated with stock head CC size also??

Also good info Matt. Learn something new everyday, thats why I love this site.

Beaflag VonRathburg

iTrader: (176)

I know it's only .002, but a few companies make forged 6.098 with both a .927 and .945 pin. Many companies also make forged pistons designed for the stock rods. I have a set of diamond 3.905 pistons, 6.098 rod, 3.622 stroke, .945 pin, with a 1.5, 1.5, 3.0 ring package. I'm going to be buying some forged 6.098 Scat H beams soon and put together a spare engine.

PICNIC_GEORGE

iTrader: (3)

Alot of the time if the piston is designed for a 6.098 rod it will have a .945 pin. Likewise alot of 6.098 rods are .945. I think all pistons designed for 6.125 and longer rods are made for a .927(standard sbc size) pin. I have never seen a 6.125 rod with an LS1 pin on it. Not saying they aren't out there.