NoShow

iTrader: (1)

Just swapping out a cam in my '04 LS6 engine and tought I'd share some info that I couldn't find beforehand.

Stock LS6 cam base circle= 1.495
Comp XR265HR Hi-lift base circle= 1.485

The stock LS6 pushrods with only 70k measure between 7.395 and 7.398 so far. Haven't measured them all yet. But that's alot of difference between pushrods! I don't know if it's just wear or poor machining. The latter, I bet.

So the answer to "do I need new pushrods" is definitely "YES DAMMIT"

So if I get 7.400 pushrods I'm still around .010 short. Any suggestions?

GMCtrk

iTrader: (27)

So does the LS6 cam have a smaller base circle than the other ls1, lq4 cams?

I'm looking at a similar cam to that comp, and I really don't want to have to change my pushrods due to a difference in base circle size.

NoShow

iTrader: (1)

I heard the 02-06 Ls6 also has longer valve stems or something, so the smaller base circle doesn't matter. Either way, just look at the recommended pushrods for your cam/engine and it will tell you what length you need. I still don't like the .010 difference between the two cams.

These stock pushrods are junk, IMO. $100 well spent on TSP or Comp hardened.

SweetS10V8

iTrader: (4)

Push rods are a good idea for any LS engine, the stock ones are weak.

You ll be just fine with aftermarket 7.400 push rods. I went with Comps .105" wall 7.400 push rods myself even before my cam swap in my LQ9. I want the stiffest push rods I can get.

Ive swapped cams to a Comp cam and I'm still running the exact same push rods without issue. Our lifter have about .200" of plunger travel.

Tootall

iTrader: (79)

the base circle should be on the cam card.

hirdlej

iTrader: (31)

What kind of preload are you shooting for? I would go for no more than .025-.050" preload.

SweetS10V8

iTrader: (4)

What makes you shoot for that range? Stock preload is more like .100-.120" IIRC

You can gain RPM and valvetrain stability by almost botoming out your hyd lifter, thats why there are "Short travel" lifters out.

NoShow

iTrader: (1)

I've never seen a cam card with the base circle on it

NoShow

iTrader: (1)

I'll have to read up on how to measure preload. I don't get how you can measure without the lifters being pumped up.

1slow01Z71

iTrader: (36)

The oil keeps them pumped up and helps the spring in the lifter. You measure Prod length with a length checker then add in the needed pre-looad. Amount of preload needed is determined by what lifters you are using. The less preload the more power you can wring out of the motor but obviously only to a certain point before the lifter starts bouncing off the lobes. The LS7 lifters have a much stouter spring in them and the cup position is also higher up. With those lifters you can run less preload, spin more rpm and get a bit more power out of them. If you're running stock lifters I wouldnt worry about running standard length pushrods.

As far as strength on stock rods, they work just fine on a single spring setup, V8 ran his 5.3 up to 7K for over a year on stock rods and 918s.