ws6togo

iTrader: (1)

I have a complete set of LS6 heads casting #243. These heads are going on my LS1 motor with a new Comp Cam. I was told that the valves are longer to compensate for the smaller base circle a typical LS6 cam (when installed in LS6 motor). I was also told that I will need longer pushrods or my valve geometry will be off (.5 inch or .050 inch.) I have a set of Comp 7.400 length rods (7955-16) will these work with the LS6 heads? I could measure the valves if I knew how long LS6 valves are supposed to be. Anyone??
Also is there a way for me to identify visually or by weight to see if the valves are the sodium filled (exhaust) or hollow (intake) valves???

TopFlite

I believe the LS6 pushrod length is 7.350.

white2001s10

iTrader: (4)

LS6 valves are 0.6mm or 0.023622" longer.
Using a 1.7:1 ratio rocker that works out to 0.0139"
or basically an extra 14 thousandths more preload in a non-adjustable system.
That's not enough to worry about if you're running non-adjustable.

kenp

iTrader: (9)

Nope. Pushrod length of LS6 is the same as LS1. That's why the LS6 has taller valve stems. The LS6 valve stem length makes up for the smaller base circle of the LS6 cam.

Whether or not you will need different pushrods will depend on the base circle of your new cam vs the LS6 cam, Head gasket thickness vs the oem .051 compressed thickness and whether or not your LS6 heads have been milled, and the lifter preload you want.

There are plenty of LS1 folks with LS6 heads and the oem length pushrods. Worst case scenario, if you do have the taller valves you may have more preload on the lifters.

You should alright. You appear to be installing an aftermarket cam with a lift that demands a base circle that's smaller than your LS1. But if you have a tendency to get **** like some of us on this board, you might want to get a adjustible pushrod and light weight checking spring for a valve and check your geometry with the swipe or wipe test. There are a bunch of threads dealing with all of this.

ws6togo

iTrader: (1)

now that makes more sense....seemed odd that valves AND pushrods needed to be longer...unless there is a new "V" shaped rocker out there ....thanks everyone

GMW-CSL

How can one determine whether you have the lightweight ZO6 valves or standard valves? How much does a lightweight, sodium filled exhaust valve and a hollow intake valve weigh?

white2001s10

iTrader: (4)

LS6 intake = 73 grams, exhaust = 65 grams
LS1 intake = 101 grams, exhaust = 94 grams

muncie21

iTrader: (14)

So for clarification in what was said above. If I'm running a Z06 (LS6) head and valve train with a stock LS1 bottom end I don't need to get longer pushrods?

FYI- I'm going with GM MLS head gaskets, heads are stock (not shaved) and the lifters and rest of the valve train is stock also.

white2001s10

iTrader: (4)

You shouldn't unless something else has been changed and overlooked.
The error should be only 0.014"
Pushrods come in .050" increments.

Xtnct00WS6

iTrader: (8)

Pushrods come in .025 increments actually...

http://www.thunderracing.com/catalog...vid=3&pcid=106

PREDATOR-Z

What cam are you running? Full specs with lifts.

white2001s10

iTrader: (4)

Thanks, that's nice to know.

CharlieLed

iTrader: (1)

One clarification to this is that these numbers are good only for 2002 and later, the 2001 LS6 heads had LS1 valves and not the hollow/sodium filled stems.