Whats the stock push rod lenth for a 2001 ls6? are they the same as the 02-04 ls6s? is it 7.4? and why do they make so many different lengths. what should i be running with a new streetable cam and 918 springs? do i need new retainers when i do the swap? any help on this would be greatly appreciated before i get deep into my winter project.

 

I'm getting ready to do the same to my 01Z. The stock push rods are 7.4. If you're not changing anything in the valve train rockers or the heads then 7.4 push rods should be fine. You should get a set of the upgraded aftermarket rods though. The various lengths come into play sometimes if you change rockers, heads, or lifters. Comp cams makes new retainers in both steel and titanium for the 918s and one or the other would probably be a good investment.

 

Just compare the base circle of the old cam vs. the new cam. Half the difference is what you need to add or remove from your pushrod length.

Example: New cam base circle measures .050 smaller than the cam removed from engine. That means the new cams base circle is .025 smaller on each side than the old cam. When the lifter is on the base circle of the new cam it will be .025 closer to the cam centerline than it was with the old cam. So you need a pushrod that is .025 longer than the one you were using with the original camshaft. If you were using the stock pushrods your new pushrod length would be 7.425.

If you were to take out your 01 LS6 cam and install a 02-04 LS6 cam and change nothing else you would need 7.425 pushrods to compensate for a .050 smaller base circle on the later LS6 cam. 02-04 LS6’s had longer valve stems so stock length pushrods could be used with the smaller base circle cam.

There are several pushrod length tools you can use too but to me it just seems easier to measure the cams.

 

I believe stock length is 7.385" but have never measured it. Pushrod length is not measured end to end (Overall Length) but rather from a point on the ball end that is 0.140" in diameter (Gauge Length). I would personally run new retainers with the 918's. The stock retainers are too loose in my opinion and I would opt for the Comp retainers that are more of a line fit. Titanium retainers will net you a couple of hundred more RPM and depending on what cam you are running may be necessary. I would personally buy machined locks as well, but that's me.

You really should buy the following if you want to ensure the setup is correct, assuming stock rocker:

1. Adjustable pushrod to measure required pushrod length
2. Valve spring micrometer to determine valve spring seat height
3. Crane valve spring tool, which allows two springs to be changed at one time and is made to fit the stock heads
4. Parts to make a tool for re-installation of the pulley
5. All required gaskets and parts

Be careful using LS1howto.com, there are several short cuts there that will get you in trouble really fast.

 

I went through a lenghtly thread on proper push rod lenght to lessen the sewing machine sound. I ended up using the "Adjustable pushrod measurer" to get the proper push rods. As mentioned using the base circle matched against the stock cam and an after market cam is one way of doing it provided you have both cams to compare by.
Good luck

Sleeper

 

good info, thanks guys. it sounds like a lot of work, ill have to figure all this stuff out before i go tearin stuff apart!

 

Its not as hard as it sounds and the tools are not real expensive but can make all the difference with the final result. Best to plan everything ahead of time and then start the install.