I have a 2005 build ls6 crate motor that has the gen 4 rods in it with floating pins & bushed rod ends. I hear the gen 4 rods are stronger then gen 3 by a bit but how about the rod bolts? I spin this motor pretty high at the drag strip, the rev limiter is set to 7200 thats where I launch it but on the data log it sees 7500 in between shifts (power shifting). Havent had an issue but when i get the car back out i plan to turn the rev limiter up to 7500 where ill be launching it in hopes of a better 60' time. I shift at 66-6800rpm so the only time it sees 7000+ is free reving or against the limiter for very short amount of time. Any one have any long term experience spinning a gen 4 ls to these kinds of rpms?

 

Id love to see these responses as im also fixing to be doing over 7,000 on the same rods and bolts

 

Yes, considerably higher RPM too. Over 8k many, many times. Stock genIV rod bolts are good to go changing them is a waste of $ imo

 

That is good to hear, Thanks for the feedback

 

The lobe, push rod pre load ( 0.0080 is what I run now ) and fresh valve springs are key. I have had better luck with beehives at high RPM than duals. I ran PAC1518 without issue and now I run PSi1511ml on EPS lobes. Shift 71/200 ish but too often it blips past 7500 during spin or too late shift. I dont have a functioning rev limiter so this wasnt planned, but it happened again and again and again. I did miss a shift once and ptv contact happened just north of 9K lol

 

 

Nothing to do with bolts, they are not the issue with RPM. Springs and lobe are the limitations so I offered up some info that might help the OP out or anyone curious about high RPM might want to know. I have put pistons and valves together at 7000RPM using duals and XE lobes before. Lobe/spring/preload is the high rpm relationship you need to focus on based on my experience

 

Gotcha, good info on the valvetrain.
I was under the impression that the rod bolts will stretch at high RPM as the crank is pulling the piston/rod down? Not sure how strong the stock gen4 bolts are though

 

I can only imagine what those parts are going through at that RPM, but they dont bust apart and I have many years on my first genIV its been rung out a TON of times. Its apart right now and the bearings show some sign of bob weight but no copper showing and the oil pressure was fine so Im going to run them again simply because I want to see how long they will go. Engines and 07 and I have almost ten years on it.

 

Word! I would add beefing up the pushrods as well, but nice post

 

Sounds like ill be fine! Thanks

 

Anyone have either experience or anything to add to those who replace the stock rod bolts with ARP 8740's, 2,000's Kateck etc...and only torque them to stock specs so that the rod ends don't need resizing/honed?

Thanks

 

What computer are you using that it saw 9k? Aftermarket I assume?

 

I'm doing this on an LS6 I'm building currently.

 

Good info Cam. My motor has 45k miles on it and has seen 7000-7500 quite a bit without a hiccup. Im running a stock ls6 cam, ls7 lifters, chromoly pushrods with .080 preload, yella terra 1.8 roller rockers and pac 1211x high rev nitrided springs. These setup seems to work well as i havent crashed the valves and it revs cleanly to 7000+

 

what year build is your ls6?

 

It's a late 2003 block.

 

Which rods?

 

Gen 3 pressed fit. Got the WS6 store HD replacement pistons that require no balancing and using ARP 2000 rod bolts torqued to something between stock and ARPs recommendation so no resizing of the rods.

 

Sounds like you have the rods out then? Why not just have the rods checked and resized?

my car is a 99, when i rebuilt the original motor i went with 8740 arps and the rods needed a hone.