Grip

I see two kit numbers. Both are described as cracked cap rod design.

134-6006 or 234-6301?

07NBSChevy

iTrader: (1)

The Pro Series (234-6301) is a stronger alloy, that is the main difference. In my opinion I would go with those. Just remember to have the rods resized with a line bore to prevent uneven clamping force which can lead to a spun bearing or worse.

KCS

iTrader: (20)

As mentioned, the 234 kit is the ARP 2000 alloy which is stronger than the 8740 alloy used in the 134 kit. The ARP 2000 alloy has a higher recommended torque value so there's a better chance that the big end bore will distort more.

I've used the ARP 2000 kit in a set with of LS3 rods and it did distort the bore, but it wasn't out of spec. I just used a "race" style bearing and set the clearances accordingly. It ran fine like that, but I'll have the engine out and apart soon due to a broken valve spring, so I can see what it looks like.

Grip

thank you!

07NBSChevy

iTrader: (1)

Keep us updated, I am interested in how everything turned out after teardown.

KCS

iTrader: (20)

They don't look as great as I had hoped. Almost all of the upper rod bearings had some wear to them, but it wasn't much. Usually that would indicate detonation or too much timing advance.

These were coated ACL Race bearings:


No sign of detonation on the pistons:

07NBSChevy

iTrader: (1)

You don't think any of that wear on the bearings is from using ARP bolts without truing the bore?

KCS

iTrader: (20)

I don't see how it could be. The wear is at 12 o'clock which is where I measured for clearance. The ID of the bearing is supposed to be elliptical with the tightest clearance at 12 and 6 o'clock and larger clearance as you measure nearer to the parting lines.

Even with the bore slightly out of round, 12 and 6 o'clock was still the tightest clearance like it's supposed to be.

JoeNova

I noticed that nobody here tried to save him any money by telling him that ARP rod bolts in gen 4 rods is pointless.

cookseyb

I just had my machine shop install ARP bolts and check the rod ends, one was so distorted I had to get a new rod. I had always thought this was BS but I guess is really is a issue.I also had my mains checked and it only took a touch-up hone job but the crank is in and torqued and it spins easily by hand and the thrust checks out...