johnster

iTrader: (27)

Do you have to change the push rods, to but it in my car,I have a 98 T/A. Thanks P.S Is it the same as the 03 LS6 cam?

LS1derfull

GM says you do thats why they changed valve lengths to compensate for reduced base circle. I would look up specs and do the math, it could work, i purposely reduced preload .050" on my setup to gain rpm with out pump up of lifters. You may be able to stray that far from what GM considers ideal. Be sure to use 918 comp springs or equivalent or you will float valves.

Tin Indian

The stock LS1 cam has a 'base circle' of 1.552" (across the lobe). That equals .775" (19.7mm) from 'cam centerline' to 'lobe heal'. In fact, GM states that this distance is in fact 19.7mm on the LS1 cam.

GM also states that the 2002 LS6 cam has a 'cam centerline' to 'lobe heal' distance of 19.0mm. That is exactly .748"



The simple math will tell you that the difference in 'cam centerline' to 'lobe heal' distance between the two cams is 0.7mm or .027". To be exact, the LS6 cam would require a .027" [longer] pushrod than the LS1 cam if you wanted to maintain the exact lifter preload as you had before the cam swap.

Now, if your heads were milled, that would decrease the .027" number by the amount that was milled from the heads.

Here is the problem: You need .027" longer rods to get the [exact] lifter preload as you had, but they only come in .050" increments.

If it was left up to me, I would install Thunder Racing 7.40" hardened rods. Why? ... They are .015" longer than your stock rods. That decreases the measurment down to .012"

Thats no problem at all. In fact, having .012" less preload than the stock spec is probably a plus, since a little less preload on the lifters will keep them from pumping up so fast at high revs.

Ron,

nuzee

iTrader: (2)

I wonder if running lash caps on the valve stems could help the geometry? What would be the ideal lash cap thickness to make up the difference using 1.7 ratio rockers?

Tin Indian

BTW ... "LS1derfull" is correct about the LS6 have a longer valve. Since they use the same pushrods as the LS1, I would bet the 2002 LS6/ZO6 Corvette hollow / sodium filled valve is just about .027" longer in total length than your stock LS1 valve.

johnster

iTrader: (27)

hey guys i have a set of 5.3 heads i am going to get ported and put them on there at the same time. so what push rods do i need?

mhoward

Wow, good info. Thanks Ron.

nuzee

iTrader: (2)

Nah, that can't be. .027" at the valve should not equal .027" at the pushrod. You need to factor in the rocker arm ratio. Other than that, your info is very good!

4thGENRETARD

Check SDPC ----->
They have a complete 02 LS6 cam swap kit and nicely priced too.

LS1derfull

You need to check wear pattern on end of valve for thickness and centering on valve, to determine if lash caps would be acceptable for you. They usually come .060" so that would be .035" difference on pushrod side of rocker.
Pretty damn close.

SSactionLs1

so is there gonna be a prob with ls1 rods?

WS6snake-eater

No there will not be a problem with the rod lenght...I have been running the cam with stock pushrods for over 6,000 miles now. The only thing I changed other than the cam was the springs. I used the GM LS6 springs, however if I had it to do all over again, I would have gone ahead and bought 918's so that I would have to buy them later on when I go to a more aggressive cam. BTW you will like the LS6 cam. It has a good pull after 4500rpm.